Antenna modulation

Abstract

There is set forth herein, in one embodiment, a method comprising inputting a carrier frequency into an antenna structure of an antenna system; inputting a digital data signal, wherein the antenna system is configured so that the digital data signal switches radiation of the antenna structure on and off.

Description

ANTENNA MODULATIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application No. 63 / 650,740, filed May 22, 2024, entitled “ANTENNA MODULATION,” which is incorporated herein by reference in its entirety.BACKGROUND

[0002] Embodiments herein relate to antennas in general and specifically to direct antenna modulation (DMA).

[0003] Antennas are often characterized by several performance metrics. The radiation pattern of an antenna indicates the distribution of emitted energy into space. An omnidirectional antenna emits energy uniformly across all horizontal directions, whereas a directional antenna focuses more energy towards specific directions. The gain of an antenna is a measure of its ability to direct energy more efficiently in a particular direction than a reference antenna, typically an isotropic antenna. The polarization of an antenna refers to the orientation of the electric field in the emitted wave. Antenna impedance is the ratio of voltage to current at its input terminals. The operational bandwidth of an antenna is the range of frequencies over which it functions effectively. The efficiency of an antenna is calculated as the ratio of power radiated to the total power input.

[0004] Antennas can also be part of an antenna array, which is a setup consisting of multiple antennas arranged in a particular geometric pattern to act as a single unit. Such arrays enhance features like gain, directivity, and beamforming capabilities that are challenging to achieve with a single antenna. Beamforming in antenna arrays is a signal processing technique that manipulates the directionality of the array's radiation pattern.

[0005] Phased array antennas are versatile, electronically controlled antenna systems capable of steering beams of radio waves in various directions without physical movement of the antennas. These systems are extensively used in applications such as radar, wireless communications, and satellite tracking, where dynamic beam steering is essential for performance.BRIEF DESCRIPTIONPage 1 of 55Attorney Docket No. 3153.148AWO

[0006] There is set forth herein, in one embodiment, a method comprising inputting a carrier frequency into an antenna structure of an antenna system; inputting a digital data signal, wherein the antenna system is configured so that the digital data signal switches radiation of the antenna structure on and off.

[0007] There is set forth herein, in one embodiment, an antenna system comprising an antenna structure; wherein the antenna system is configured to apply a carrier signal to the antenna structure; and control circuitry configured to receive a baseband signal and to switch radiation of the antenna structure on and off in dependence on the baseband signal.

[0008] There is set forth herein, in one embodiment, a method comprising inputting a carrier frequency into an antenna of an antenna system; inputting a digital data signal into the antenna, wherein the antenna system is configured so that the digital data signal switches radiation of the antenna on and off.

[0009] There is set forth herein, in one embodiment, an antenna system comprising an antenna structure; a frequency selective surface disposed in a radiating path of the antenna structure; a feed network coupled to the antenna structure and configured to deliver a continuous-wave carrier signal thereto; and a modulation control circuit configured to receive a baseband digital signal and to control a state of the frequency selective surface based on the baseband digital signal, wherein the antenna structure is energized with the continuous-wave carrier signal and radiates the carrier signal through the frequency selective surface when the frequency selective surface is in a transparent state, such that the emitted wave is modulated in accordance with the baseband digital signal.

[0010] There is set forth herein, in one embodiment, an antenna system comprising an antenna structure; a frequency selective surface disposed in a radiating path of the antenna structure; wherein the antenna system is configured to transmit a continuous-wave carrier signal to the antenna structure; wherein the antenna system is further configured to control a state of the frequency selective surface in dependence on a baseband digital signal; and wherein the antenna structure is energized with the continuous-wave carrier signal and radiates the carrier signal through the frequency selective surface when the frequency selective surface is in a transparentPage 2 of 55Attorney Docket No. 3153.148AWOstate so that an emitted wave emitted by the antenna system is modulated in accordance with the baseband digital signal.

[0011] There is set forth herein, in one embodiment, an antenna system comprising an antenna structure; a frequency selective surface disposed forward of the antenna structure; a feed network applying a carrier signal to the antenna structure, wherein the antenna structure radiates a continuous wave; and a modulation control circuit receiving a baseband digital signal and controlling the frequency selective surface based on the baseband digital signal, wherein the antenna system emits a modulated carrier wave modulated by the baseband signal.

[0012] There is set forth herein, in one embodiment, a method of designing and evaluating a modulated antenna system, comprising establishing a simulation framework configured to simulate an antenna structure and a digital modulation input that modulates radiation characteristics of the antenna structure based on a digital signal.

[0013] There is set forth herein, in one embodiment, a method of designing a digitally modulated antenna system, comprising establishing a full-wave electromagnetic simulation framework configured to model a phased array antenna structure in conjunction with a frequency selective surface (FSS) positioned in the near-field region of the antenna structure; injecting a carrier signal into the antenna structure through a feed network; and simulating modulation of radiation based on a digital control signal applied to switching elements of the FSS to toggle between radiating and non-radiating states.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Fig. 1 is a schematic diagram illustrating an antenna system configured to operate according to a Direct Antenna Modulation (DAM) scheme, with a Frequency Selective Surface (FSS) structure serving as a switching element.

[0015] Fig. 2A depicts the received modulated electric field radiated from the designed DAM-based phased array.

[0016] Fig. 2B shows the frequency spectrum of the received modulated signal.

[0017] Fig. 2C illustrates the achieved sideband power level for different modulation frequencies.Page 3 of 55Attorney Docket No. 3153.148AWO

[0018] Fig. 2D presents the signal-to-noise ratio (SNR) for various modulation frequencies.

[0019] Fig. 3 presents the simulated bit error rate (BER) as a function of signal-to-noise ratio (SNR) for different data rates.

[0020] Fig. 4A provides an illustration of the FSS-based DAM applied to an electrically small dipole antenna. The cylindrical FSS, embedded with switching elements, is wrapped around the antenna within its near-field region, with both isometric and side views shown.

[0021] Fig. 4B shows the input impedance of the DAM system when the FSS behaves as a transparent layer (radiating mode).

[0022] Fig. 4C depicts the input impedance of the DAM system when the FSS functions as a reflector (non-radiating mode).

[0023] Fig. 4D depicts the radiation pattern of the DAM system in radiating mode.

[0024] Fig. 4E illustrates the radiation pattern of the DAM system in the non-radiating mode.

[0025] Fig. 5A shows a two-element phased array antenna designed for high-frequency data transmission.

[0026] Fig. 5B presents the testing setup, showcasing the phased array antenna used as a transmitter and a wideband antenna used as a receiver.

[0027] Fig. 5C displays the received time-domain signal, showing a sequence of zeros and ones transmitted from the phased array antenna and captured at the receiver side.

[0028] Fig. 5D presents the transmitted frequency spectrum, showing the characteristics of the signal generated by the phased array antenna.

[0029] One or more aspects of the present invention are particularly pointed out and distinctly claimed as examples in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:DETAILED DESCRIPTIONPage 4 of 55Attorney Docket No. 3153.148AWO

[0030] Referring now to Fig. 1, an example of antenna system 100 is illustrated schematically. Antenna system 100 can include antenna structure 102, feed network 110 coupled to antenna structure 102, modulation control circuit 120, and frequency selective surface (FSS) 140 disposed in radiating path 150 of antenna structure 102. The system can be configured to emit a modulated electromagnetic wave 160 based on a baseband signal representing information content to be transmitted.

[0031] Feed network 110 can be configured to deliver a conti nuous-wave (CW) carrier signal to antenna structure 102. In some implementations, feed network 110 can include one or more impedance-matched transmission line structures, such as coaxial lines, microstrip lines, or stripline paths. Feed network 110 can also incorporate passive RF elements such as impedance transformers, phase shifters, combiners, or baluns depending on the configuration of antenna structure 102. Feed network 110 can be designed to maintain broadband or narrowband impedance matching to maximize power transfer efficiency to antenna structure 102.

[0032] Antenna structure 102 can be any type of radiating structure. In one embodiment, antenna structure 102 can be a single radiating element, such as a dipole, monopole, loop, or microstrip patch antenna. In another embodiment, antenna structure 102 can include an array of radiating elements forming a phased array antenna, configured to steer its radiation pattern via electronically controlled phase differences between array elements. Regardless of configuration, antenna structure 102 can be excited by feed network 110 with a carrier signal, which may be a sinusoidal tone at a selected RF frequency.

[0033] FSS 140 can be disposed along radiating path 150 of antenna structure 102. FSS 140 can be fabricated as a planar surface comprising an array of periodic conductive features 142 supported on a dielectric substrate 144. Each conductive feature 142 can include or be electrically connected to one or more active switching elements 146, such as PIN diodes, varactor diodes, or MEMS switches, which can be driven into conducting or non-conducting states based on applied control signals.

[0034] Modulation control circuit 120 can be configured to receive baseband signal 122, representing the information content to be transmitted, and to generate a control waveform 124 that is applied to active switching elements 146 of FSS 140. Control waveform 124 can be a digitalPage 5 of 55Attorney Docket No. 3153.148AWOsignal such as a square wave or pulse train, and can be delivered to FSS 140 through one or more bias lines 126. Modulation control circuit 120 can include one or more logic devices, such as a field-programmable gate array (FPGA), microcontroller, or custom hardware logic, that generates control waveform 124 in real time.

[0035] In various embodiments, control waveform 124 can be time-synchronized to the carrier signal delivered via feed network 110. Such synchronization can reduce transient artifacts, including near-field ringing or spectral distortion, that may otherwise occur when switching FSS 140 rapidly. Time alignment can also ensure deterministic modulation behavior and improve spectral purity of the resulting modulated signal.

[0036] Modulated electromagnetic wave 160 emitted from antenna system 100 can be a carrier wave modulated in amplitude, phase, or both, depending on the configuration of control waveform 124 and the properties of FSS 140. In a representative implementation, when FSS 140 is in a transparent state, the electromagnetic field generated by antenna structure 102 can pass through FSS 140 substantially unimpeded. When FSS 140 is in a reflective state, surface currents induced on conductive features 142 can re-radiate energy in such a way that transmission through FSS 140 is suppressed or redirected.

[0037] FSS 140 can be implemented in either a planar configuration, such as a metasurface layer mounted parallel to the antenna aperture, or a closed or partially enclosed shell configuration (Fig.4 A) that surrounds antenna structure 102 and includes one or more controllable apertures or slits through which modulated radiation can escape. In either case, switching of active elements 146 in synchrony with baseband signal 122 can result in dynamic modulated wave 160 being emitted from antenna system 100, effectively encoding digital information onto the carrier wave using spatial gating techniques.

[0038] In some embodiments, the modulation scheme can be on-off keying (OOK), wherein FSS 140 alternates between transparent and reflective states in accordance with logical 1 and 0 bits, respectively, of baseband signal 122. In other embodiments, amplitude shift keying (ASK), pulsewidth modulation, or phase-tuned gating can be implemented using variable-capacitance or multilevel control elements embedded in FSS 140. The design of modulation control circuit 120 and thePage 6 of 55Attorney Docket No. 3153.148AWOtiming of control waveform 124 can be selected to implement a desired modulation scheme while minimizing power loss and RF distortion.

[0039] The architecture shown in Fig. 1 enables modulation of an electromagnetic carrier without direct RF-domain switching within feed network 110. This can preserve impedance matching and reduce system complexity by decoupling RF signal generation from digital modulation control. The radiating function of antenna structure 102 remains linear and unmodulated, while FSS 140 and modulation control circuit 120 impose the desired modulation at the final electromagnetic interface with free space.

[0040] Feed network 110 can be configured to receive a carrier signal 101 from carrier signal source 112, and to apply carrier signal 101 to antenna structure 102. Carrier signal 101 can be characterized by a carrier frequency. Carrier signal source 112 can include any RF signal generation system capable of producing a continuous-wave signal at a selected transmission frequency. In various embodiments, carrier signal source 112 can comprise a radio frequency transmitter, transceiver, signal synthesizer, local oscillator, or frequency up conversion chain. Carrier signal source 112 can also include signal conditioning components such as low-noise amplifiers (LNAs), power amplifiers (PAs), filters, frequency multipliers, isolators, and impedance-matching networks. In some configurations, carrier signal source 112 can form part of a transmit / receive (T / R) module, software-defined radio platform, or a backend signal processing system associated with a communication, radar, or sensing application. The output of carrier signal source 112 can be coupled to feed network 110 through a direct electrical connection, waveguide, or coaxial interface.

[0041] Modulation control circuit 120 can be configured to receive baseband signal 122 from data source 128, and to generate control waveform 124 that drives FSS 140 based on the contents of baseband signal 122. Data source 128 can include any digital logic system, processor, or communication interface configured to generate or relay binary or multilevel digital data to be transmitted. In various implementations, data source 128 can comprise a microprocessor, digital signal processor (DSP), field-programmable gate array (FPGA), microcontroller, memory-mapped register interface, network interface card (NIC), sensor system, or software application generating telemetry, command, audio, video, or control data. Data source 128 can provide baseband signalPage 7 of 55Attorney Docket No. 3153.148AWO122 via a wired or wireless interface, and can optionally implement protocols such as UART, SPI, I2C, Ethernet, USB, or custom digital buses depending on system requirements.

[0042] Embodiments herein recognize that frequency selective surface (FSS) 140 operates as a dynamic spatial modulator that controls electromagnetic wave transmission based on the conductivity state of a patterned grid. When switching elements embedded in FSS 140 — such as PIN diodes — are biased into a conducting state by modulation control circuit 120, the periodic structure of FSS 140 behaves as a transparent surface for the carrier signal. In this "on" or transparent state, the grid elements are effectively shorted, allowing the impinging electromagnetic wave to pass through the surface with minimal reflection, due to impedance matching between FSS 140 and free space. Embodiments herein recognize that the spatial periodicity of the conductive pattern is designed to support transmission resonance at the operating frequency, enabling constructive interference and minimal reactive loading.

[0043] In contrast, when the switching elements are biased into a non-conducting state by modulation control circuit 120, the same periodic structure behaves as a reflective surface. In this "off1or non-transparent state, FSS 140 behaves capacitively or presents high impedance discontinuities, effectively forming a partial electromagnetic bandgap. This results in destructive interference and significant wave reflection at the FSS interface. Embodiments herein recognize that in this state, FSS 140 suppresses forward transmission and confines the electromagnetic energy near antenna structure 102, thereby enabling near-field energy storage and preventing radiation into the far field.

[0044] Accordingly, by toggling FSS 140 between its transparent and reflective states under the control of modulation control circuit 120, embodiments herein achieve precise temporal control over antenna radiation. This enables direct antenna modulation (DAM) without modifying the feed network or the physical geometry of antenna structure 102.

[0045] Embodiments herein recognize that an antenna system architecture in which antenna structure 102 radiates an unmodulated continuous-wave carrier signal can offer substantial design and performance advantages compared to architectures that directly modulate the RF signal within the feed network. In such systems, feed network 110 can be configured to deliver carrier signal 101Page 8 of 55Attorney Docket No. 3153.148AWOto antenna structure 102 in an impedance-matched condition without including modulation circuitry or high-speed switching elements.

[0046] Because carrier signal 101 is not modulated or switched within feed network 110, the impedance of the feed path remains substantially static, linear, and narrowband or broadband as needed. This simplifies the design of matching networks between carrier signal source 112 and antenna structure 102, and allows for stable operation across operating temperature, frequency, and loading conditions. Embodiments herein recognize that impedance matching is easier to implement and maintain in such systems due to the absence of time-varying reactive components or transient switching events within the signal path.

[0047] In particular, the architecture described herein facilitates the design of feed network 110 using only passive components, such as transmission lines, impedance transformers, capacitors, inductors, baluns, and power dividers. Feed network 110 can be implemented without active RF components such as mixers, RF switches, high-speed digital signal processors (DSPs), or voltage-controlled attenuators (VCAs), which would otherwise introduce non-linearities, parasitics, and matching discontinuities. The use of a passive, unmodulated feed network improves signal integrity and reduces power consumption, insertion loss, and manufacturing complexity.

[0048] Embodiments herein also recognize that systems employing gated aperture architectures, such as FSS 140, can face unique challenges. When FSS 140 is placed in a reflective state, energy from antenna structure 102 can accumulate in the near field, especially in close proximity to the surface, forming standing waves or reactive energy buildup. If not properly managed, this stored energy can lead to transient ringing, undesired back-coupling into the antenna feed, or distortion of the radiated waveform when FSS 140 switches to a transparent state.

[0049] To mitigate these challenges, FSS 140 can be designed with low-Q resonant elements, short carrier dwell times in the reflective state, or electromagnetic damping structures. In one embodiment, control waveform 124 can be configured to limit the maximum duration for which FSS 140 remains reflective, or to employ intermediate impedance states to bleed off stored energy.

[0050] Antenna system 100 can be configured to exhibit synchronization behavior in which switching transitions of frequency selective surface (FSS) 140 align with specific temporal characteristics of the electromagnetic environment in the near field of antenna structure 102. In one Page 9 of 55Attorney Docket No. 3153.148AWOembodiment, antenna system 100 supports a configuration in which transitions between transparent and reflective states of FSS 140 occur at about the temporal peak of reactive energy stored in the near field of antenna structure 102. This condition enables antenna system 100 to operate in an energy-synchronous direct antenna modulation (DAM) mode, characterized by modulation transitions that are naturally aligned to the energy dynamics of the radiating structure rather than to any fixed phase point of the carrier signal.

[0051] Energy-synchronous behavior can enhance system performance by improving radiation efficiency, spectral clarity, and modulation fidelity. Aligning the timing of FSS 140 transitions with the local maximum of stored near-field energy can facilitate more complete extraction of radiated energy during the "on" (transparent) state, while suppressing spurious emissions during the "off1(reflective) state. In representative implementations, the energy accumulation and release patterns in the near-field region of antenna structure 102 naturally define preferred switching intervals, which can be pre-characterized using simulation or calibration. Timing waveforms governing switching behavior can be defined in dependence on these intervals, without requiring dynamic sensing or closed-loop feedback.

[0052] In addition to energy-synchronous configurations, antenna system 100 can support phasebased synchronization schemes. For example, switching transitions of FSS 140 can be defined to occur at consistent phase locations of carrier signal 101, such as zero crossings, rising edges, or other deterministic points. Such phase-based approaches may offer advantages in systems requiring stable timing alignment between a digital baseband signal and an RF carrier waveform, or in configurations emphasizing waveform repeatability or spectral purity.

[0053] Synchronization behavior in antenna system 100 can be supported through use of synchronization signal 125, which is schematically shown in Fig. 1 as being sourced from feed network 110. In various embodiments, synchronization signal 125 can be derived internally within feed network 110, or alternatively, originated externally from a signal processing block, carrier signal generator, or dedicated timing subsystem that monitors characteristics of carrier signal 101 or models system energy behavior.

[0054] When synchronization signal 125 is sourced internally, feed network 110 can incorporate circuitry such as zero-crossing detectors, envelope detectors, or phase-locked loops (PLLs) toPage 10 of 55Attorney Docket No. 3153.148AWOextract timing information from carrier signal 101. A PLL -based configuration can lock to the frequency and phase of carrier signal 101 and generate a reference clock or subharmonic signal suitable for use by modulation control circuit 120. In other implementations, synchronization signal 125 can be derived from energy model predictions or empirical time-delay profiles associated with known antenna geometries and feed conditions.

[0055] When synchronization signal 125 is sourced externally, the signal can originate from a baseband processor, waveform scheduler, control FPGA, or digital timing controller that is logically upstream of both feed network 110 and modulation control circuit 120. In such configurations, synchronization signal 125 may represent an abstraction of energy timing based on stored models or pre-programmed switching logic. The signal can be communicated to modulation control circuit 120 via a digital bus, dedicated timing line, or embedded synchronization channel, allowing deterministic switching behavior to be implemented regardless of the origin of carrier signal 101.

[0056] The signal associated with reference numeral 125 in Fig. 1 can serve a dual role in antenna system 100. In addition to conveying synchronization timing, signal 125 can function as a communication channel between feed network 110 (or an external synchronization source) and modulation control circuit 120. This dual-purpose role enables synchronization signal 125 to carry metadata about modulation intervals, waveform type, phase offsets, or timing uncertainty windows, thereby enhancing the flexibility of timing control and supporting programmable or adaptive synchronization behaviors.

[0057] In one example implementation, synchronization signal 125 can take the form of a square wave or digital pulse train, with rising or falling edges aligned to predicted or measured moments of near-field energy maxima. Modulation control circuit 120 can use these timing edges as triggers or gating events to control the application of control waveform 124 to switching elements 146 of FSS 140. In some configurations, programmable delays or phase offsets can be applied to signal 125 within modulation control circuit 120 to shift the timing of switching events by a calibrated interval, thereby aligning transitions with energy peaks or desired carrier phase conditions.

[0058] By structuring antenna system 100 to support both energy-synchronous and phase-synchronous behaviors, and by allowing synchronization signal 125 to originate from eitherPage 11 of 55Attorney Docket No. 3153.148AWOinternal or external sources, the architecture provides a flexible foundation for realizing advanced DAM implementations. Synchronization to near-field energy dynamics in particular enables antenna system 100 to efficiently exploit stored electromagnetic energy during modulation events, facilitating high spectral efficiency, low sideband distortion, and improved performance in compact or phased-array antenna platforms.

[0059] In various embodiments, antenna structure 102 can be configured as a phased array comprising a plurality of antenna elements arranged in a linear, planar, or conformal geometry. Each element of the phased array can be operatively coupled to feed network 110, which is configured to control the relative phase and amplitude of the signals supplied to each antenna element. Through such control, feed network 110 enables the array to perform a wide range of advanced functions associated with phased array operation, including but not limited to electronic beam steering, beam shaping, multi-beam generation, adaptive nulling, and spatial interference suppression.

[0060] In particular, feed network 110 can include components such as digital phase shifters, variable gain amplifiers, or true-time-delay circuits to provide fine-grained control over the excitation of each array element. This allows the radiated beam to be steered dynamically across a desired angular sector without requiring mechanical movement of antenna structure 102.Additionally, in some embodiments, feed network 110 may support time-varying or real-time control of beam parameters, enabling tracking of moving targets or responsive adaptation to dynamic environmental conditions.

[0061] When used in conjunction with the FSS-based Direct Antenna Modulation (DAM) architecture described herein, the phased array implementation of antenna structure 102 provides an enhanced platform for spatiotemporally dynamic modulation. That is, the system can simultaneously steer beams and modulate the radiated waveform using the FSS layer as a highspeed gating mechanism. This combination allows for novel functionality such as directiondependent modulation schemes, angle-sensitive encoding, or multi-user signaling with spatial separation and time-domain modulation embedded into the radiation pattern.

[0062] Embodiments herein recognize that conventional antennas and phased arrays are often constrained by inherent trade-offs among bandwidth, efficiency, and physical size. As the physicalPage 12 of 55Attorney Docket No. 3153.148AWOdimensions of the antenna decrease, bandwidth and radiation efficiency typically suffer, fundamentally limited by the Wheeler-Chu-Harrington and Bode-Fano bounds. These constraints are particularly severe for compact and electrically small antennas, leading to diminished system performance. Various passive methods and non-Foster active circuit techniques have attempted to mitigate these limits, but with limited success and increased design complexity.

[0063] To address these limitations, embodiments herein introduce a novel Direct Antenna Modulation (DAM) architecture that enables significantly broader bandwidth operation without requiring complex feed structures or active RF-domain modulation. As shown in Fig. 1, DAM can be implemented using FSS 140, positioned in the near field of antenna structure 102. In this architecture, antenna structure 102 can be any suitable radiator, including a phased array, while modulation is imparted by FSS 140 acting as a dynamic electromagnetic aperture.

[0064] Feed network 110 can be configured to deliver a continuous-wave (CW) carrier signal to antenna structure 102. In some implementations, feed network 110 can include one or more impedance-matched transmission line structures, such as coaxial lines, microstrip lines, or stripline paths, and may incorporate passive RF elements such as impedance transformers, baluns, or phase shifters to support broadband impedance matching.

[0065] Embodiments herein recognize that prior DAM systems were constrained by integration of switching circuitry within either the antenna element or the feed network, which introduced reactive impedance variation and impaired matching. As shown by FSS 140 of Fig. 1, modulation in this architecture is applied externally to the feed network, thereby preserving impedance characteristics and simplifying design. This separation also avoids the need for complex wideband feed circuitry typical of prior ultrawideband phased arrays, such as Vivaldi, TCA, or PUMA arrays.

[0066] Antenna structure 102 can be configured as a phased array comprising a plurality of radiating elements arranged in a linear, planar, or conformal geometry. Each array element can be fed by feed network 110, which is configured to control the relative phase and amplitude of the excitation signals. This enables beam steering, multi-beam formation, and adaptive spatial filtering. Feed network 110 can include phase shifters, variable gain amplifiers, or true-time-delay circuits for dynamic pattern control.Page 13 of 55Attorney Docket No. 3153.148AWO

[0067] As shown in Fig. 1, FSS 140 can comprise periodic conductive features 142 fabricated on dielectric substrate 144, and include switchable elements 146 such as PIN diodes or MEMS devices. These switching elements can be controlled by control waveform 124, generated by modulation control circuit 120 based on a baseband signal 122 received from data source 128.

[0068] Embodiments herein recognize that prior implementations of DAM lack the spatial resolution and scalability needed for phased arrays. To overcome this, full-wave electromagnetic simulations were used to evaluate energy dynamics and establish synchronization conditions for the FSS-based DAM system. As shown by FSS 140 of Fig. 1, modulation transitions can be timed to coincide with the peak of stored near-field energy to ensure energy-synchronous DAM behavior.

[0069] As further illustrated by the E-field plots of Fig. 2A, switching FSS 140 between a transparent and reflective state allows binary bitstreams to be directly encoded into the radiated waveform. In the radiating state (bit 1), antenna structure 102 emits energy that passes through FSS 140, while in the non-radiating state (bit 0), energy is confined in the near-field region.

[0070] Fig. 2B shows the resulting spectrum, with a 10 GHz carrier and distinct sidebands at 8 GHz and 12 GHz for a 2 GHz baseband rate. Sideband power levels of 4.5 V / m and 2.7 V / m confirm successful modulation.

[0071] Embodiments herein recognize that increasing the baseband modulation frequency expands bandwidth, but also introduces noise and waveform distortion, reducing sideband clarity, as shown in Fig. 2C. This trade-off defines a practical upper bound on modulation frequency. The system's spectral performance and signal-to-noise ratio (SNR) for different baseband / digital frequencies are further illustrated in Fig. 2D. Fig. 3 presents the simulated bit error rate (BER) as a function of SNR across multiple data rates, demonstrating robust performance under realistic channel conditions.

[0072] Fig. 4A shows a cylindrical implementation of FSS 140 surrounding an electrically small dipole. Figs. 4B and 4D illustrate impedance and radiation patterns in the radiating mode while Figs. 4C and 4E show the corresponding parameters in the reflective state. Figs. 4B and 4C show the impedance of dipole antenna in radiating (free space) and non radiating state respectively, and 4D and 4E shows the radiation pattern of dipole in radiating and non radiating states respectively. These configurations confirm that the DAM technique is adaptable to diverse antenna structures.Page 14 of 55Attorney Docket No. 3153.148AWO

[0073] Taken together, this system demonstrates that DAM-enabled phased arrays, as implemented via FSS 140 of Fig. 1, can achieve broad bandwidth, simplified architecture, and robust modulation performance. By decoupling radiation and modulation mechanisms, and synchronizing switching with near-field energy dynamics, this energy-synchronous DAM configuration overcomes critical limitations of traditional antenna systems and represents a compelling solution for high-throughput wireless applications.

[0074] Embodiments herein recognize that conventional antennas and phased arrays are often constrained by inherent trade-offs among bandwidth, efficiency, and physical size, wherein a reduction in size typically leads to diminished bandwidth and performance. Embodiments herein present a novel design methodology based on Direct Antenna Modulation (DAM), which enables significantly broader bandwidths compared to traditional approaches. Further, embodiments herein extend the DAM concept to phased array antennas for the first time, demonstrating that arrays designed using this technique can achieve wideband operation with remarkably simple architectures.

[0075] In one aspect, embodiments herein provide a DAM topology utilizing Frequency Selective Surfaces (FSS), offering a more practical and less complex implementation than conventional DAM configurations, particularly for phased arrays. Architectures herein are evaluated using fullwave electromagnetic simulations, and a detailed wireless link analysis is performed to assess system-level performance. The simulation framework used for these evaluations enables end-to-end characterization of DAM-enabled systems, underscoring their potential for next-generation high-performance wireless applications. In one embodiment, a 4 * 4 antenna array based on the described DAM FSS architecture is simulated and analyzed, achieving a wide bandwidth ratio of 15:1 while maintaining critical performance metrics such as signal -to-noise ratio (SNR), bit error rate (BER), and sideband power levels within the desired operational range.

[0076] Embodiments herein recognize that compact and electrically small antennas, which occupy minimal physical space while meeting system performance requirements, are crucial for various applications, including wireless communication systems, loT, wearable devices, and augmented reality [1-4], However, embodiments herein recognize that passive, linear time-invariant electrically small antennas are fundamentally constrained by electromagnetic principles, leading to significant limitations on bandwidth and radiation efficiency. As recognized by embodiments Page 15 of 55Attorney Docket No. 3153.148AWOherein, as the size of such antennas decreases, both bandwidth and efficiency deteriorate dramatically, as dictated by the Wheeler-Chu-Harrington limit [5-7],

[0077] Moreover, embodiments herein recognize that the communication data rate — a key metric for evaluating the performance of a wireless link — is directly tied to bandwidth and radiation efficiency, and such physical limitations inherently restrict overall system performance [8], Various passive approaches, such as optimized electrically small spherical electric dipole antennas [9] and designs incorporating high-permeability magnetic coatings

[0010] , have been proposed to approach these fundamental limits. However, embodiments herein recognize that these approaches often involve highly complex and sometimes impractical structures. Significant research has also been devoted to improving the bandwidth of electrically small antennas through passive, linear time-invariant impedance matching techniques [11, 12], Yet, despite these efforts, embodiments herein recognize that none of these designs have come close to reaching the theoretical bound. The inability to reach the theoretical bound is primarily attributed to the fundamental constraint imposed by the Bode-Fano limit on impedance matching, which applies to all passive linear timeinvariant systems

[0013] ,

[0078] Embodiments herein recognize that one potential approach to getting closer to, or potentially surpassing, these fundamental bounds involves violating one of the underlying assumptions of the passive linear time-invariant system model, thereby transitioning to an active, non-linear, or time-variant system. For example, one approach can involve using non-Foster impedance matching techniques that incorporate active negative impedance converter networks

[0014] , which enable the realization of negative inductors and capacitors [15, 16], However, embodiments herein recognize that such methods often rely on complex, power-intensive active circuits that face critical challenges, including stability issues, noise management difficulties, and parasitic effects — factors that significantly limit design flexibility and operational bandwidth. While challenging to implement, antenna system 100 can advantageously incorporate non-Foster matching techniques in some embodiments.

[0079] Embodiments herein recognize that time modulation-based matching networks have also been proposed for bandwidth improvement

[0017] , However, embodiments herein recognize that emphasis on additional biasing circuitry, fast switching, precise synchronization, and mitigation of phase distortion has limited the practical applicability of time-modulated networks. Additionally,Page 16 of 55Attorney Docket No. 3153.148AWOembodiments herein recognize that some of these techniques rely on coupling energy between radiative and non-radiative modes, rendering them unsuitable for achieving high-efficiency operation. While such techniques are non-trivial to deploy, antenna system 100 can advantageously incorporate time-modulated matching networks in certain embodiments.

[0080] Embodiments herein recognize that phased array antennas, composed of multiple individual radiating elements excited with precise phase control, offer enhanced performance compared to single-element antennas, yet still encounter similar limitations in bandwidth, physical size, and radiation efficiency as electrically small antennas. These arrays enable critical functionalities such as high gain, adaptive beamforming, electronic scanning, and support for high-data-rate communication links. As a result, phased array antennas play a vital role in a wide range of applications, including radar systems, wireless communication networks, MIMO systems, satellite communications, and radio astronomy. In particular, the increasing demand for faster data transmission and multi-band operation has created a pressing need for ultrawideband phased array antennas capable of operating efficiently without compromising performance.

[0081] Embodiments herein recognize that over the past few decades, various ultrawideband phased array architectures have been developed, including tapered slot antenna systems such as Vivaldi arrays

[0018] , tightly coupled dipole arrays (TCAs)

[0019] , planar ultrawideband modular antenna (PUMA) arrays

[0020] , and substrate-integrated waveguide (SlW)-based antenna arrays

[0021] , among others. However, despite these advancements, existing architectures are often limited by factors such as electrical size, radiation performance, or implementation complexity. For example, embodiments herein recognize that systems like Vivaldi arrays, while capable of achieving extremely wide bandwidths (up to 10: 1), tend to suffer from bulkiness and radiation loss.Similarly, architectures such as TCAs and PUMAs typically require wideband feeding circuits that must match the bandwidth of the antenna elements, which further contributes to increased system complexity and physical footprint.

[0082] Embodiments herein apply DAM FSS architectures to both single-antenna and multiantenna systems, such as phased arrays, marking a significant advancement in overcoming key performance limitations. Embodiments herein provide a Frequency Selective Surface (FSS)-based DAM topology that is applicable to a wide range of antenna systems and substantially improves design flexibility, particularly in the context of phased arrays. Further, embodiments herein Page 17 of 55Attorney Docket No. 3153.148AWOintroduce a full-wave simulation framework for DAM analysis, offering greater accuracy than approaches that rely primarily on equivalent circuit models, which may not capture the relevant physical interactions inherent in radiating structures.

[0083] Accordingly, embodiments herein present a comprehensive solution for designing highly efficient antennas and ultra-wideband, low-profile phased arrays. The solution is engineered with an emphasis on structural and electrical flexibility, enabling integration with virtually any antenna system architecture beyond the constraints of traditional narrowband or broadband configurations. Embodiments herein evaluate the DAM concept not only from an antenna design standpoint but also in terms of its effect on wireless link performance, including key communication metrics such as bandwidth, data rate, and bit error rate (BER) for DAM-based phased array systems.

[0084] Embodiments herein recognize that Direct Antenna Modulation (DAM) is a transmission technique in which the electromagnetic behavior of the antenna is dynamically altered in real time to encode wideband information. In contrast to conventional systems — where an RF signal is premodulated with digital data and then fed into a passive antenna — DAM employs digital control signals to directly influence the radiation properties of the antenna.

[0085] Through direct switching of the radiating structure, DAM enables precise on-off transitions that encode information as narrow pulses. These high-speed transitions result in the generation of broadband spectral content. Because the modulation occurs through changes in radiation state rather than by modifying a carrier waveform upstream, the method eliminates the need for conventional analog modulation chains and reduces the dependency on wideband RF front-end components. As a result, electrically small antennas can radiate broadband signals, thereby overcoming geometric limitations imposed by traditional antenna design.

[0086] Embodiments herein recognize that switching the antenna between radiating and nonradiating states at precisely controlled intervals inherently produces wideband spectral components due to the abrupt time-domain changes. According to Fourier analysis, the sharp transitions — whether toggling into or out of a radiating condition — expand bandwidth.

[0087] By employing rapid transitions in FSS behavior — such as switching between transparent and reflective states as shown by FSS 140 of Fig. 1 — DAM architectures facilitate broadband operation even when the underlying antenna structure 102 is intrinsically narrowband. The Page 18 of 55Attorney Docket No. 3153.148AWOdecoupling of bandwidth from structural geometry allows compact or form -factor-constrained antennas to support applications requiring high data throughput, agile spectrum access, and burstmode communication, where legacy modulation methods would be insufficient.

[0088] Embodiments herein recognize that the foundation for what is now referred to as Direct Antenna Modulation (DAM) dates back to the 1950s and 1960s, when time-varying circuits were employed to enhance the bandwidth performance of high-Q very low frequency (VLF) antennas [22-24], Such bandwidth enhancement efforts were pursued through two primary approaches: one approach involved modulating the antenna reactance via time-varying matching networks synchronized with frequency-shift keying (FSK) modulation

[0024] , while another employed On-Off Keying (OOK) schemes to suppress residual transients and improve spectral efficiency

[0022] , Embodiments herein recognize that a concept analogous to modern DAM was also explored in early active integrated antennas

[0025] , wherein a microstrip antenna printed on a silicon substrate functioned as a diode-based switch. However, embodiments herein recognize that the slow charge dynamics of the semiconductor material limited the achievable bandwidth.

[0089] Embodiments herein recognize that the advent of high-speed solid-state switching devices has facilitated the practical implementation of DAM at radio frequencies [26, 27],

[0090] Embodiments herein recognize that a key factor influencing the performance of DAM systems is the interaction between time-varying control elements and the near-field dynamics of the antenna, particularly the reactive (or stored) energy associated with the radiating structure. DAM systems that do not preserve or synchronize switching events with the behavior of stored reactive energy are classified as non-energy-synchronous DAM. Embodiments herein recognize that nearly all early implementations of DAM [23, 24, 26-28] fall into thisnon-energy-synchronous category, which significantly constrained their ability to enhance the efficiency-bandwidth product. This limitation is primarily attributed to intrinsic energy losses introduced when abrupt switching events disrupt the storage and recovery of reactive energy.

[0091] For example, embodiments herein recognize that short-circuiting a charged capacitor or open-circuiting an inductor carrying nonzero current results in immediate dissipation of stored energy. Embodiments herein recognize that in the context of antenna systems, such eventsPage 19 of 55Attorney Docket No. 3153.148AWOcorrespond to the loss of near-field energy, which is typically represented as lumped capacitive or inductive elements in the antenna’s equivalent circuit model.

[0092] To address this challenge, embodiments herein can implement control schemes that precisely synchronize switching events with the time-dependent evolution of the antenna’s near-field energy. Embodiments herein recognize that DAM systems maintaining such synchronization are referred to as energy-synchronous DAM — a concept originally introduced in theoretical form in

[0022] , Embodiments herein recognize that over the past several years, experimental demonstrations of this concept have emerged using a range of fundamental digital modulation formats, including amplitude modulation

[0029] , frequency-shift keying (FSK) [30-33], and phase-shift keying (PSK)

[0034] ,

[0093] Embodiments herein further recognize that identified currently proposed DAM implementations — regardless of whether they are energy-synchronous or non-energy-synchronous, and irrespective of the selected digital modulation scheme — have been limited to single-antenna systems.

[0094] Embodiments herein present a DAM architecture that can be implemented in either a single-antenna system or a multi-antenna system, such as phased array antennas. Embodiments herein recognize that phased arrays play a critical role in high-gain applications and form the foundation of modern wireless communication and sensing systems. However, embodiments herein recognize that achieving wide bandwidth in such systems inherently requires complex feeding networks, which can limit scalability and practical deployment. By incorporating the DAM technique, embodiments herein enable enhancements in bandwidth, efficiency, and gain, while simultaneously reducing system complexity and improving the overall performance and adaptability of phased array antennas.

[0095] Embodiments herein recognize that implementing DAM in phased arrays presents significant challenges, as directly integrating switching elements into the radiating elements or the feeding network is extremely difficult and often impractical.

[0096] In one embodiment, embodiments herein provide a DAM implementation that leverages a frequency selective surface (FSS) positioned in front of the array. The FSS functions as a dynamic switching layer, controlling radiation by modulating its transmission properties. Fig. 1 illustrates Page 20 of 55Attorney Docket No. 3153.148AWOthe application of the DAM technique using an FSS in a phased array antenna configuration.Referring to Fig. 1, unlike alternative DAM implementations where the switching circuit is integrated into the radiating elements or the feeding network, the switching circuit is positioned on the FSS, which resides within the near field of the phased array.

[0097] In reference to Fig. 1, when the digital signal toggles the switching circuit on the FSS, the surface alternates between a transparent state and a perfectly reflecting state. In the “on” state, the FSS behaves as a transparent layer, allowing radiation from the phased array to pass through, functioning similarly to a conventional antenna system. In contrast, during the “off’ state, the FSS behaves as a perfect reflector, effectively blocking the outgoing radiation.

[0098] In one embodiment, antenna structure 102 of Fig. 1 is provided as a 4><4 phased array operating at 10 GHz, and frequency selective surface (FSS) 140 incorporates PIN diodes as switching elements. The state of the FSS can be dynamically modulated by digital control signals input by modulation control circuit 120, which in turn modulates the RF signal radiated by antenna structure 102. The described time-domain modulation enhances the spectral content of the radiated waveform.

[0099] Embodiments herein recognize that previous implementations of the DAM concept have relied exclusively on the antenna’s equivalent circuit model to estimate near-field (reactive energy) dynamics. In these prior approaches, embodiments herein recognize that switching timing was synchronized based on the transient response of the equivalent circuit, which was considered to reflect the behavior of the actual stored energy within the antenna. However, embodiments herein recognize that this equivalent circuit representation may not always be accurate, as it constitutes a simplified abstraction and may fail to fully capture the complex spatiotemporal dynamics of the true near-field energy.

[0100] Embodiments herein further recognize that extending the equivalent circuit-based DAM analysis to phased array antennas is extremely challenging, due to the difficulty of accurately modeling the collective near-field interactions among multiple array elements. To address this limitation, embodiments herein provide a simulation framework capable of conducting full-wave 3D electromagnetic simulations of DAM operation, thereby capturing near-field energy dynamics with high fidelity.Page 21 of 55Attorney Docket No. 3153.148AWO

[0101] A simulation framework for testing and configuring antenna system 100 for increased bandwidth operation is set forth in reference to Example 1.

[0102] Example 1

[0103] A simulation framework was established for testing and configuring antenna system 100 for increased bandwidth operation, as set forth in reference to Example 1.

[0104] To further illustrate the concept, a 4 x 4 antenna array integrated with an FSS positioned in the near-field region was simulated according to the architecture shown in Fig. 1. A digital control (data) signal in dependence on baseband signal 122 was applied to the FSS to operate embedded switches, enabling direct modulation of the antenna’s radiation characteristics. Moreover, the spatial configuration of the phased array and FSS was optimized to maximize reactive energy storage during the “on” state and suppress far-field signal leakage during the “off’ state. This configuration ensured precise synchronization between the switching events and the dynamics of the stored reactive energy, making the system an energy-synchronous DAM.

[0105] Furthermore, to evaluate the wireless link performance of the DAM system in simulation, a computationally efficient approach was adopted. Specifically, a point sensor was strategically placed in the far field of the transmitting antenna to act as a surrogate for a conventional receiving antenna. The point sensor captured the radiated electromagnetic fields and provided signal measurements that closely approximate those of a typical receiver, enabling accurate field analysis while significantly reducing simulation overhead. Consequently, a cleaner transmission of binary sequences (ones and zeros) was achieved, as shown in Fig. 1.

[0106] The simulation setup was utilized to evaluate system performance under various modulation frequencies. A comprehensive analysis was conducted based on simulated results, focusing on key performance metrics including signal power level, signal-to-noise ratio (SNR), and bit error rate (BER). The influence of different modulation frequencies on these parameters is discussed in detail in subsequent sections. Additionally, the simulation framework enabled detailed investigation of reactive energy dynamics within the phased array in the presence of the FSS. This capability facilitated precise extraction of the optimal digital modulation frequency to synchronize the switching events effectively. As a result, the overall system operated as an energy-synchronous DAM, achieving a high efficiency-bandwidth product.Page 22 of 55Attorney Docket No. 3153.148AWO

[0107] To further illustrate the system’s operation, an RF signal at 10 GHz was fed into the antenna array. In the radiating state (representing bit ‘1’), the antenna not only emitted radiation but also accumulated reactive energy in its near-field region. Since the near field required a finite amount of time to reach its maximum energy level, a brief initial delay was introduced before applying the modulation signal to ensure the system fully settled into its steady-state behavior. The resulting electric field (E-field) magnitudes were recorded, allowing precise identification of the optimal switching moment when the antenna stored maximum reactive energy.

[0108] For the transmission of bit ‘O’, the FSS was switched “off’, thereby preventing radiation and confining the energy within the near field, maintaining it at the maximum stored level without leakage. The E-field distribution results, presented in Fig. 2A, clearly demonstrated the modulation behavior for the binary bitstream, with distinguishable field profiles corresponding to bit ‘ 1 ’ (radiating) and bit ‘0’ (non-radiating).

[0109] Fig. 2B illustrates the spectrum of the modulated electric field radiated by the system. The primary carrier tone was observed at 10 GHz, with a peak field strength of 6.9 V / m. Distinct sidebands appeared at 8 GHz and 12 GHz, corresponding to a 2 GHz baseband modulation, indicating a total occupied bandwidth of 4 GHz. These sidebands exhibited strong amplitudes of 4.5 V / m (lower sideband) and 2.7 V / m (upper sideband), well above the noise floor. This spectral signature confirmed the successful implementation of the energy-synchronous DAM concept.

[0110] Ideally, sideband levels are expected to be approximately half the amplitude of the carrier; however, the observed asymmetry was attributed to spatial non-uniformities, particularly in the placement or orientation of the receiving antenna or point sensor. Although simulations were performed across a range of modulation frequencies, only the results corresponding to a 2 GHz baseband signal are presented here for clarity and to avoid overcomplication in spectral interpretation.

[0111] It was noted that as the modulation frequency increases, the bandwidth of the spectrum increases. This behavior was consistent with the theoretical expectation that the 3 dB (half-power) bandwidth of a modulated signal is approximately twice the modulation frequency. Therefore, higher baseband rates led to broader spectral occupancy, which can be exploited for wideband and high-throughput energy-synchronous DAM applications. The spectral clarity and strength of thePage 23 of 55Attorney Docket No. 3153.148AWOsidebands in the 2 GHz case exemplified the modulation scheme’s robustness, scalability, and spectral agility.

[0112] While the theoretical upper limit for the baseband modulation frequency is that it must remain below the carrier frequency (to avoid spectral aliasing and maintain sideband integrity), the simulation results revealed a more practical constraint. Specifically, as the baseband frequency increased, the modulated waveform accumulated higher-frequency spectral content, which amplified the system’s susceptibility to noise and waveform distortion. This effect resulted in a noticeable suppression of the sideband power levels at higher modulation rates.

[0113] To systematically investigate this limitation, a detailed spectral analysis was performed across multiple modulation frequencies. As illustrated in Fig. 2C, the sideband amplitudes progressively diminished with increasing baseband frequency. This reduction in spectral energy was attributed to both the rising influence of high-frequency noise and the diminishing efficiency of near-field energy modulation at faster switching rates. Consequently, although the theoretical bandwidth expansion scaled linearly with modulation frequency (i.e., approximately twice the baseband rate), the usable or effective bandwidth was ultimately bounded by the system’s ability to preserve strong and distinguishable sidebands.

[0114] This observed trend underscored a critical design trade-off in energy-synchronous DAM, where higher baseband rates provided greater bandwidth and data throughput but simultaneously posed challenges to modulation fidelity and spectral efficiency. The analysis presented in Fig. 2C quantitatively captured this trade-off by illustrating the degradation in sideband power levels as a function of increasing baseband frequency, thereby providing essential insight into the practical modulation limits of the energy-synchronous DAM architecture.

[0115] Embodiments herein recognize that in addition to sideband power suppression, a further performance constraint was observed in the form of signal-to-noise ratio (SNR) degradation at elevated baseband modulation rates. As switching frequency increased, the modulation process became increasingly susceptible to spectral dispersion and temporal misalignment, which introduced higher-order noise components into the radiated waveform. A corresponding reduction in spectral purity and overall SNR was observed, as illustrated in Fig. 2D, where a clear downward trend in SNR appeared with increasing modulation frequency. The resulting performance limitationPage 24 of 55Attorney Docket No. 3153.148AWOimposed a practical ceiling on the achievable baseband rate, thereby underscoring the importance of jointly optimizing modulation speed and spectral fidelity in energy-synchronous DAM implementations. A lowered SNR was further observed to impact system-level reliability by directly increasing bit error rate (BER), in view of the inverse relationship between SNR and BER given as:

[0117] where Eb is energy of bit, No is noise power, Rb is bit rate and B is the bandwidth of antenna system. The BER of designed system is obtained using the equation below:

[0118] BER = -e~Eb / N° (2)

[0119] The inverse relationship between SNR and BER was demonstrated in Fig. 3, where increased SNR levels yielded exponentially improved BER performance, while lower SNR levels corresponded to substantially elevated error rates. The chart of Fig. 3 further depicted BER behavior as a function of SNR across varying data rates, highlighting the pronounced effect of data rate on overall system robustness. At elevated data rates, individual bit durations became shorter, effectively reducing the bit energy, and increasing the system’s susceptibility to noise and distortion. As a result, transmissions at higher data rates exhibited significantly higher BER under the same SNR conditions compared to transmissions at lower data rates. This performance pattern underscored the fundamental trade-off between throughput and reliability, particularly in noiselimited or bandwidth-constrained environments.

[0120] The frequency-selective surface (FSS)-based DAM configuration was further extended to single-antenna and electrically small antenna systems, which typically radiated power in omnidirectional or weakly directive patterns. In such use cases, the FSS structure did not remain confined to planar implementations but instead adopted geometries such as cylindrical, spherical, or other enclosing surfaces positioned within the near-field region of the antenna. These geometries were selected to store and regulate reactive near-field energy in all directions, thereby enabling temporally synchronized switching behavior aligned with field dynamics.

[0121] To illustrate such an implementation, an electrically small electric dipole was employed, exhibiting an omnidirectional radiation pattern as depicted in Fig. 4A. A cylindrical FSS integrated Page 25 of 55Attorney Docket No. 3153.148AWOwith a switching circuit was constructed and wrapped around the dipole within its reactive near field as shown in Fig. 4A. When a digital control signal (baseband signal) modulated the state of the switching circuit, the FSS alternated between a transparent regime and a high-reflectivity regime approximating a perfect electric conductor (PEC). As shown in Fig. 4B, the input impedance of the antenna system in the ‘on’ state, i.e., when the FSS is transparent, closely matches that of a conventional antenna without the FSS, resulting in similar radiation behavior. This behavior is further confirmed by the radiation pattern shown in Fig.4C. Input impedance measurements in this state, as shown in Fig. 4B, confirmed that radiation was sustained and efficiently matched. In the ‘on’ state, when the FSS was transparent, the input impedance of the antenna system closely approximated that of a conventional unshielded dipole, producing a comparable radiation pattern as shown in Fig. 4D.

[0122] As shown in Fig. 4B, the input impedance of the antenna system in the ‘on’ state, i.e., when the FSS is transparent, closely matches that of a conventional antenna without the FSS, resulting in similar radiation behavior. This behavior is further confirmed by the radiation pattern shown in Fig.4C.

[0123] In the “off’ state, i.e., when the FSS acts as a perfect electric conductor (PEC), the input impedance of the antenna system becomes highly reactive with a negligible real component, as illustrated in Fig. 4D. This indicates that radiation is effectively suppressed, as evident from the radiation pattern shown in Fig. 4E. Hence, modulation of the antenna’s radiation successfully achieved using this method, enabling ultra-wideband operation.

[0124] Although performance metrics of Figs. 4B-4E are set forth in reference to an embodiment with a cylindrical FSS, similar behavior can be replicated using other enclosed surfaces, such as a spherical FSS, provided they are positioned within the near field of the antenna.

[0125] The FSS-based DAM architecture can be employed for both phased array and singleantenna systems, and is broadly applicable to any antenna architecture. Furthermore, while the current discussion has focused on implementing DAM through amplitude modulation, the concept can be readily extended to support other modulation schemes such as frequency shift keying (FSK), phase shift keying (PSK), and beyond.Page 26 of 55Attorney Docket No. 3153.148AWO

[0126] Based on the above simulation results, an optimized configuration for the antenna system was derived by identifying the digital modulation frequency and FSS switching parameters that maximized spectral clarity, reactive energy efficiency, and signal fidelity. By analyzing the electric field magnitudes, sideband behavior, and bit error performance across varying modulation scenarios, the simulation framework enabled data-driven refinement of both the antenna array geometry and FSS layout. As a result, the design was converged toward a high-performance operating point suitable for wideband and energy-efficient communication systems.

[0127] Specifically, establishing a finalized design for the antenna system can include defining a set of candidate array geometries and FSS configurations, each varying in element spacing, switching topology, and modulation parameters. These configurations can then be simulated across a range of digital control signal profiles to assess near-field energy accumulation, radiated field characteristics, and modulation timing behavior. Electromagnetic field data and system-level metrics — such as signal-to-noise ratio, bit error rate, and spectral occupancy — can be extracted from each simulation run and evaluated to identify parameter sets that provide optimal performance. Control timing for digital switching can be refined to align with the carrier waveform’s zero-crossing points or peak reactive energy moments, ensuring minimal phase distortion and enhanced spectral clarity. A final configuration can then be selected based on a balance of communication performance and implementation practicality, and carried forward for fabrication, integration, or deployment within operational systems.

[0128] [end of Example 1]

[0129] Embodiments herein present an efficient energy-synchronous Direct Antenna Modulation system that enables significant bandwidth enhancement achieving up to a 15:1 bandwidth expansion while maintaining critical performance metrics such as sideband power levels, signal-to-noise ratio (SNR), and bit error rate (BER). Through comprehensive full-wave EM simulations and frequency-domain analysis, embodiments herein demonstrate the generation of strong and distinguishable sidebands, validating the successful realization of the energy-synchronous DAM concept. Embodiments herein investigate the fundamental limitations of the system by analyzing the impact of increasing baseband frequency on SNR and BER. Embodiments herein reveal that while higher modulation rates lead to broader spectral occupancy, they also can introduce degradation in SNR and sideband power, thereby elevating BER. However, depending on specific Page 27 of 55Attorney Docket No. 3153.148AWOsystem requirements, such as tolerable BER thresholds or limited communication range, these trade-offs can be managed. The energy-synchronous DAM framework presents a flexible and scalable approach for realization of high-speed, compact, and energy-efficient wireless communication systems.

[0130] Phased array antennas are versatile, electronically controlled antenna systems capable of steering beams of radio waves in various directions without physical movement of the antennas. These systems are extensively used in applications such as radar, wireless communications, and satellite tracking, where dynamic beam steering is essential for performance.

[0131] Embodiments herein recognize that one of the primary drawbacks of phased array antennas is their generally narrow bandwidth. This limitation arises from the inherent bandwidth limits of individual electrically small antenna elements that are usually utilized as the building blocks of these arrays. These bandwidth constraints can significantly impact the versatility and efficiency of phased arrays in scenarios requiring wide frequency coverage. In response to this challenge, embodiments herein provide a solution leveraging the innovative approach of direct antenna modulation (DAM) technique to fulfill the requirements of wideband phased array antennas while maintaining a low-profile design.

[0132] Embodiments herein recognize that DAM can facilitate wideband capabilities in phased array designs without compromising the system’s profile. While DAM has been successfully utilized in simple patch antennas, its application has been limited in scope. Embodiments herein recognize that to implement the DAM concept to phased array antennas, configurations can benefit from control of energy stored in the near field of the array. Embodiments herein recognize that controlling near field array energy storage can be more challenging for an antenna array having a relatively larger area near field as compared to a single antenna having a relatively smaller area near field. Antenna system configurations featuring near field energy storage control can overcome traditional bandwidth constraints of antenna arrays and can open new possibilities in antenna array technology, enhancing frequency bandwidth in wireless communication applications.

[0133] Embodiments herein recognize that the fundamental concept of DAM lies in its ability to dynamically alter the near field characteristics of antenna elements. Embodiments herein canPage 28 of 55Attorney Docket No. 3153.148AWOachieve dynamically alteration of near field characteristics by switching on and off the radiation of the antenna.

[0134] An antenna system herein can be configured so that while radiation is off energy stored in the nearfield of the antenna is kept building of. The pattern of the switching can be dictated by the incoming digital data (zeros and ones). In this scenario, instead of upconverting the incoming digital signal and then transmitting it using the antenna, antenna systems herein can employ the digital signal to switch the diode so that the antenna selectively transmits its fundamental frequency when it is allowed (zeros). The nearfield of the antenna can be configured to exhibit targeted characteristics. Ideally, there should be no radiation leakage from the antenna when it is not supposed to radiate. On the other hand, the antenna should start radiating right away when it is supposed to radiate. Engineering the nearfield distribution is a challenging task even for a single antenna. Antenna systems herein can be configured to avoid radiation leakage from the antenna when the antenna is not supposed to radiate. Antenna systems herein can be configured so that the antenna radiates immediately when it is supposed to radiate.

[0135] Example 2

[0136] To demonstrate the viability of this concept for phased array antenna, an experiment was carried out using a two-element phased array structure for a simple patch antenna, which is depicted in Fig. 5A. The antenna can include first and second ports connected to first and second respective feeding lines. The feeding lines can define a feed network. The first feeding line can be the input for RF carrier frequency into the antenna and the second feeding line can be the input for the digital data signal into the antenna. The digital signal is responsible for switching a diode configured for turning on and off (switching) the radiation of the antenna. Additionally, respective patch antennas of the array are designed with the capability for independent feeding, allowing the direction of the radiation to be adjusted according to specific requirements. The results reported in Figs. 5C and 5D demonstrate that the two-element phased array antenna is indeed capable of transmitting data at 240 MHz, which is seven times greater than the native frequency bandwidth of the antenna array. This substantial increase in bandwidth capability of a phased array antenna highlights the effectiveness of using DAM for phased array structures, establishing capabilities for high-frequency data transmission far exceeding its baseline specifications.Page 29 of 55Attorney Docket No. 3153.148AWO

[0137] In reference to Fig. 5A, a two-element phased array antenna is shown, designed to support high-frequency data transmission with beamforming capabilities suitable for advanced wireless systems. Fig. 5B illustrates the corresponding experimental setup, in which the phased array antenna is configured as a transmitter and a wideband antenna is used as the receiver, enabling over-the-air validation of system-level performance. As shown in Fig. 5C, the time-domain signal received at the wideband antenna clearly reproduces the binary sequence of zeros and ones transmitted by the phased array, confirming the DAM system’s ability to accurately encode and radiate digitally modulated signals. Fig. 5D presents the transmitted frequency spectrum, highlighting the broadband spectral content generated by the DAM-based modulation approach, and demonstrating the capability of the phased array antenna to support wideband signal generation suitable for high-speed communication applications.

[0138] [End of Example 2]

[0139] Embodiments herein can include alternative architectures. In one embodiment, an antenna array can be provided in the form of a waveguide slot antenna array controlled with DAM control methodologies set forth herein. A waveguide slot array can feature an enclosed configuration, facilitating simplified nearfield antenna control.

[0140] Embodiments herein recognize that in existing communication systems, low frequency data is mixed with the career signal (to bring it to the higher frequencies) and then is transmitted through a phased array antenna. In antenna systems herein, radiation of the phased array antenna can be directly switched using an incoming digital signal. Embodiments herein can enable phased arrays to transmit data with bandwidth much higher than their radiation bandwidth overcoming a bottleneck in antenna design. Embodiments herein can feature different phased array antenna architectures including, e g., patch arrays, phased arrays using leaky and cavity based elements.

[0141] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”), “contain” (and any formPage 30 of 55Attorney Docket No. 3153.148AWOcontain, such as “contains” and “containing”), and any other grammatical variant thereof, are open-ended linking verbs. As a result, a method or article that “comprises”, “has”, “includes” or “contains” one or more steps or elements possesses those one or more steps or elements, but is not limited to possessing only those one or more steps or elements. Likewise, a step of a method or an element of an article that “comprises”, “has”, “includes” or “contains” one or more features possesses those one or more features, but is not limited to possessing only those one or more features.

[0142] Terms like “obtainable” or “definable” and “obtained” or “defined” are used interchangeably. This, for example, means that, unless the context clearly dictates otherwise, the term “obtained” does not mean to indicate that, for example, an embodiment must be obtained by, for example, the sequence of steps following the term “obtained” though such a limited understanding is always included by the terms “obtained” or “defined” as a preferred embodiment.

[0143] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the subject matter disclosed herein. In particular, all combinations of claims subject matter appearing at the end of this disclosure are contemplated as being part of the subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

[0144] This written description uses examples to disclose the subject matter, and also to enable any person skilled in the art to practice the subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

[0145] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described examples (and / or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particularPage 31 of 55Attorney Docket No. 3153.148AWOsituation or material to the teachings of the various examples without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various examples, they are by no means limiting and are merely exemplary. Many other examples will be apparent to those of skill in the art upon reviewing the above description. The scope of the various examples should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Forms of term “based on” herein encompass relationships where an element is partially based on as well as relationships where an element is entirely based on. Forms of the term “defined” encompass relationships where an element is partially defined as well as relationships where an element is entirely defined. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f) unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure. It is to be understood that not necessarily all such objects or advantages described above may be achieved in accordance with any particular example. Thus, for example, those skilled in the art will recognize that the systems and techniques described herein may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0146] The terms “substantially”, “approximately”, “about”, “relatively”, or other such similar terms that may be used throughout this disclosure, including the claims, are used to describe and account for small fluctuations, such as due to variations in processing, from a reference or parameter. Such small fluctuations include a zero fluctuation from the reference or parameter as well. For example, they can refer to less than or equal to ± 10%, such as less than or equal to ± 5%, such as less than or equal to ± 2%, such as less than or equal to ± 1%, such as less than or equal to ± 0.5%, such as less than or equal to ± 0.2%, such as less than or equal to ± 0.1%, such as less than or equal to ± 0.05%. If used herein, the terms “substantially”, “approximately”, “about”, “relatively,” or other such similar terms may also refer to no fluctuations, that is, ± 0%. It is contemplated that numerical values, as well as other values that are recited herein can be modified Page 32 of 55Attorney Docket No. 3153.148AWOby the term “about”, whether expressly stated or inherently derived by the discussion of the present disclosure. Further, any description of a range herein can encompass all subranges.

[0147] The terms “connect,” “connected,” “contact” “coupled” and / or the like are broadly defined herein to encompass a variety of divergent arrangements and assembly techniques. These arrangements and techniques include, but are not limited to (1) the direct joining of one component and another component with no intervening components therebetween (z.e., the components are in direct physical contact); and (2) the joining of one component and another component with one or more components therebetween, provided that the one component being “connected to” or “contacting” or “coupled to” the other component is somehow in operative communication (c. ., electrically, physically, optically, etc.) with the other component (notwithstanding the presence of one or more additional components therebetween). It is to be understood that some components that are in direct physical contact with one another may or may not be in electrical contact with one another. Moreover, two components that are electrically connected, electrically coupled, optically connected, optically coupled, may or may not be in direct physical contact, and one or more other components may be positioned therebetween.

[0148] While the subject matter has been described in detail in connection with only a limited number of examples, it should be readily understood that the subject matter is not limited to such disclosed examples. Rather, the subject matter can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the subject matter. Additionally, while various examples of the subject matter have been described, it is to be understood that aspects of the disclosure may include only some of the described examples. Also, while some examples are described as having a certain number of elements it will be understood that the subject matter can be practiced with less than or greater than the certain number of elements. Accordingly, the subject matter is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

[0149] All publications cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein as though fully set forth.Page 33 of 55Attorney Docket No. 3153.148AWO

[0150] Subject matter incorporated by reference is not considered to be an alternative to any claim limitations, unless otherwise explicitly indicated.

[0151] Where one or more ranges are referred to throughout this specification, each range is intended to be a shorthand format for presenting information, where the range is understood to encompass each discrete point within the range as if the same were fully set forth herein.

[0152] While several aspects and embodiments of the present disclosure have been described and depicted herein, alternative aspects and embodiments may be affected by persons having ordinary skill in the art to accomplish the same objectives. Accordingly, this disclosure and the appended claims are intended to cover all such further and alternative aspects and embodiments as fall within the true spirit and scope of the present disclosure.

[0153] The following reference(s) are incorporated herein by reference in their entireties and a skilled person is considered to be aware of disclosure of these references.REFERENCES1. Lin, W., Ziolkowski, R. W. & Huang, J. Electrically small, low-profde, highly efficient, huygens dipole rectennas for wirelessly powering intemet-of-things devices. IEEE Transactions on Antennas and Propagation 67, 3670-3679 (2019).2. Jemaludin, N. H. B. et al. A comprehensive review on mimo antennas for 5g smartphones:Mutual coupling techniques, comparative studies, sar analysis, and future directions. Results in Engineering 102712 (2024).3. Ikram, M., Sultan, K., Lateef, M. F. & Alqadami, A. S. A road towards 6g communication — a review of 5g antennas, arrays, and wearable devices. Electronics 11, 169 (2022).4. Hu, P. F., Leung, K. W., Pan, Y. M. & Zheng, S. Y. Electrically small, planar, horizontally polarized dual-band omnidirectional antenna and its application in a mimo system. IEEE Transactions on Antennas and Propagation 69, 5345-5355 (2021).5. Chu, L. J. Physical limitations of omni-directional antennas. Journal of applied physics 19, 1163-1175 (1948).Page 34 of 55Attorney Docket No. 3153.148AWO6. Wheeler, H. A. Fundamental limitations of small antennas. Proceedings of the IRE 35, 1479- 1484 (1947).7. Harrington, R. F. Effect of antenna size on gain, bandwidth, and efficiency 1. Journal of Research of the National Bureau of Standards: Radio propagation. D 63 (1959).8. Shannon, C. E. Communication in the presence of noise. Proceedings of the IRE 37, 10- 21(1949).9. Das, S. & Iyer, A. K. Design of a highly miniaturized, inherently matched, spherical folded dipole antenna and evaluation of its quality factor. IEEE Transactions on Antennas and Propagation 69, 8914-8919 (2021).10. Kim, O. S. Electric dipole antennas with magnetic-coated pec cores: Reaching the chu lower bound on q. IEEE transactions on antennas and propagation 60, 1616-1619 (2011).11. Best, S. R. Low q electrically small linear and elliptical polarized spherical dipole antennas.IEEE Transactions on Antennas and Propagation 53, 1047-1053 (2005).12. Sussman-Fort, S. E. & Rudish, R. M. Non-foster impedance matching of electrically-small antennas. IEEE Transactions on Antennas and Propagation 57, 2230-2241 (2009).13. Fano, R. M. Theoretical limitations on the broadband matching of arbitrary impedances.Journal of the Franklin Institute 249, 57-83 (1950).14. Shih, T.-Y. & Behdad, N. Wideband, non-foster impedance matching of electrically small transmitting antennas. IEEE Transactions on Antennas and Propagation 66, 5687-5697 (2018).15. Linvill, J. Transistor negative-impedance converters. Proceedings of the IRE 41, 725-729 (1953).16. Jacob, M. M. & Sievenpiper, D. F. Non-foster matched antennas for high-power applications.IEEE Transactions on Antennas and Propagation 65, 4461-4469 (2017).Page 35 of 55Attorney Docket No. 3153.148AWO17. Fritts, Z., Babaee, A., Young, S. M. & Grbic, A. Space-time modulation of a multimode electrically small antenna for increased matching and efficiency bandwidths. IEEE Transactions on Antennas and Propagation (2024).18. Chen, Z.-F., Tu, Z.-H., Lin, C.-H. & Cheng, Y.-H. 300 ghz low-cost pcb vivaldi antenna array and transition structure to wr-3 waveguide. IEEE Access (2024).19. Zhao, L. et al. An ultrawideband dual-polarized tightly coupled dipole array (tcda) with wide scanning range. IEEE Antennas and Wireless Propagation Letters 23, 1961-1965 (2023).20. Sun, D.-M. et al. A planar uhf-band ultrawideband modular antenna array with tapered probes feed. IEEE Transactions on Antennas and Propagation 72, 1483-1496 (2024).21. Askarzadeh, R., Farahbakhsh, A., Zarifi, D. & Zaman, A. U. Wideband high efficiency slot array antenna based on gap waveguide single-layer feeding network. IEEE Antennas and Wireless Propagation Letters (2024).22. Galejs, J. Switching of reactive elements in high-q antennas. IEEE Transactions on Communications Systems 11, 254-255 (1963).23. Johannessen, P. Automatic tuning of high-q antenna for vlf fsk transmission. IEEE Transactions on Communications Systems 12, 110-115 (1964).24. Wolff, H. High-speed frequency-shift keying of If and vlf radio circuits. IRE Transactions on Communications Systems 5, 29-42 (1957).25. Fusco, V. F. & Chen, Q. Direct-signal modulation using a silicon microstrip patch antenna.IEEE Transactions on Antennas and Propagation 47, 1025-1028 (1999).26. Xu, X., Jing, H. C. & Wang, Y. E. High speed pulse radiation from switched electrically small antennas. In 2006 IEEE Antennas and Propagation Society International Symposium, 167-170 (IEEE, 2006).27. Wang, X., Katehi, L. P. & Peroulis, D. Time-varying matching networks for signal-centric systems. IEEE transactions on microwave theory and techniques 55, 2599-2613 (2007).Page 36 of 55Attorney Docket No. 3153.148AWO28. Keller, S. D., Palmer, W. D. & Joines, W. T. Switched antenna circuit with increased information bandwidth. IEEE Antennas and Wireless Propagation Letters 9, 1045-1048 (2010).29. Azad, U. & Wang, Y. E. Direct antenna modulation (dam) for enhanced capacity performance of near-field communication (nfc) link. IEEE Transactions on Circuits and Systems I: Regular Papers 61, 902-910 (2013).30. Srivastava, S. & Adams, J. J. Transmission of a broadband fsk signal from a dynamically tuned narrowband antenna. IET Microwaves, Antennas and Propagation 14, 1651-1654 (2020).31. Santos, J. P. D., Fereidoony, F., Hedayati, M. & Wang, Y. E. High efficiency bandwidth vhf electrically small antennas through direct antenna modulation. IEEE Transactions on Microwave Theory and Techniques 68, 5029-5041 (2020).32. Salehi, M., Manteghi, M., Suh, S.-Y., Sajuyigbe, S. & Skinner, H. G. A wideband frequency shift keying modulation technique using transient state of a small antenna. Progress In Electromagnetics Research 143, 421-445 (2013).33. Santos, J. P. D., Bhakta, K., Fereidoony, F. & Wang, Y. E. Onto a higher power handling for very high frequency direct antenna modulation. IET Circuits, Devices and Systems 16, 373- 381 (2022).34. Zhu, R. & Wang, Y. E. A modified qpsk modulation technique for direct antenna modulation (dam) systems. In 2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 1592-1593 (IEEE, 2014).Page 37 of 55Attorney Docket No. 3153.148AWO

Claims

1. CLAIMS2.What is claimed is:

1. A method comprising:4.inputting a carrier frequency into an antenna structure of an antenna system;5.inputting a digital data signal, wherein the antenna system is configured so that the digital data signal switches radiation of the antenna structure on and off.

2. The method of claim 1, wherein the antenna system includes a diode responsive the digital data signal configured for turning on and off the radiation of the antenna.

3. The method of claim 1, wherein the antenna system is configured so that radiation of the antenna is on when ones of the digital data signal are received.

4. The method of claim 1, wherein the antenna system is configured so that radiation of the antenna is off when zeroes of the digital data signal are received.

5. The method of claim 1, wherein the antenna system is configured so that radiation of the antenna is on when ones of the digital data signal are received, wherein the antenna system is configured so that radiation of the antenna is off when zeroes of the digital data signal are received.

6. The method of claim 1, wherein the antenna is an antenna of an antenna array.

7. The method of claim 1, wherein the antenna structure includes a phased array of antennas.

8. The method of claim 1, wherein the antenna structure includes a phased array of antennas, and wherein the method includes controlling the phased array of antennas according to a beamforming algorithm.

9. The method of claim 1, wherein the antenna structure includes a phased array of antennas, wherein the antenna system is configured so that radiation of the antenna is on when ones of the digital data signal are received, wherein the antenna system is configured so that radiation of the antenna is off when zeroes of the digital data signal are received.14.Page 38 of 5515.Attorney Docket No. 3153.148AWO 10. The method of claim 1 , wherein the antenna system includes a diode responsive the digital data signal configured for turning on and off the radiation of the antenna, wherein the antenna structure includes a phased array of antennas, wherein the antenna system is configured so that radiation of the antenna is on when zeroes of the digital data signal are received, wherein the antenna system is configured so that radiation of the antenna is off when ones of the digital data signal are received.

11. The method of claim 1, further comprising positioning a frequency selective surface (FSS) in front of the antenna structure, such that the FSS is located in the near-field region of the antenna structure.

12. The method of claim 1, wherein the FSS comprises switching elements configured to toggle between a transparent state and a reflective state based on the digital data signal.

13. The method of claim 1, further comprising applying the carrier signal to the antenna structure through a feed network, wherein the antenna structure radiates a continuous wave independently of the digital data signal.

14. The method of claim 1, further comprising using a modulation control circuit to receive the digital data signal and to control the switching state of the FSS in synchronization with the digital data signal.

15. The method of claim 1, wherein controlling the switching state of the FSS modulates the carrier signal radiated from the antenna structure, thereby generating a time-domain modulated carrier wave corresponding to the digital data signal.

16. The method of claim 1, wherein switching of radiation on and off is temporally aligned to about a maximum of stored near-field energy of the antenna structure.

17. The method of claim 1, wherein switching of radiation of the antenna structure is implemented by controlling a frequency selective surface (FSS) disposed in a radiating path of the antenna structure, and wherein control of the FSS is timed in accordance with a synchronization signal derived from the carrier frequency.

18. The method of claim 1, wherein the antenna system comprises a modulation control Page 39 of 5524.Attorney Docket No. 3153.148AWO circuit configured to control a frequency selective surface (FSS) disposed in a radiating path of the antenna structure, wherein the modulation control circuit is configured to initiate state transitions of the FSS at about time points corresponding to maxima in stored near-field energy of the antenna structure, and wherein the timing of the state transitions is determined based on a synchronization signal derived from the carrier frequency and indicative of energy buildup in the near-field region of the antenna structure.

19. An antenna system comprising:26.an antenna structure;27.wherein the antenna system is configured to apply a carrier signal to the antenna structure; and28.control circuitry configured to receive a baseband signal and to switch radiation of the antenna structure on and off in dependence on the baseband signal.

20. The antenna system of claim 19, wherein the control circuitry comprises at least one switching device responsive to the baseband signal and configured to control radiation of the antenna structure based on values of the baseband signal.

21. The antenna system of claim 19, wherein the antenna system is configured such that radiation of the antenna structure is enabled when the baseband signal corresponds to a first binary value.

22. The antenna system of claim 19, wherein the antenna system is configured such that radiation of the antenna structure is suppressed when the baseband signal corresponds to a second binary value.

23. The antenna system of claim 19, wherein the antenna system is configured such that radiation of the antenna structure is enabled when the baseband signal corresponds to a first binary value and is suppressed when the baseband signal corresponds to a second binary value.

24. The antenna system of claim 19, wherein the antenna structure comprises a phased array of radiating elements.34.Page 40 of 5535.Attorney Docket No. 3153.148AWO 25. The antenna system of claim 19, further comprising a frequency selective surface (FSS) positioned in front of the antenna structure in a near-field region, the FSS including switching elements configured to dynamically toggle between transparent and reflective states.

26. The antenna system of claim 19, further comprising a modulation control circuit configured to receive the baseband signal and to synchronize switching of the antenna structure to occur at about a temporal peak of stored near-field energy associated with the antenna structure.

27. The antenna system of claim 19, wherein the control circuitry is configured to determine a timing point for switching based on detection of a peak in near-field reactive energy stored by the antenna structure.

28. The antenna system of claim 19, wherein the modulation control circuit is configured to control the frequency selective surface (FSS) such that state transitions of the FSS occur at about a time corresponding to a maximum in stored near-field energy of the antenna structure, and wherein timing of the state transitions is determined based on a synchronization signal derived from the carrier signal and representative of energy buildup in the near-field region.

29. The antenna system of claim 19, wherein the modulation control circuit is configured to cause the antenna system to emit a time-domain modulated carrier wave corresponding to the baseband signal.

30. A method comprising:41.inputting a carrier frequency into an antenna of an antenna system;42.inputting a digital data signal into the antenna, wherein the antenna system is configured so that the digital data signal switches radiation of the antenna on and off.

31. The method of claim 30, wherein the antenna system includes a diode responsive the digital data signal configured for turning on and off the radiation of the antenna.

32. The method of claim 30, wherein the antenna system is configured so that radiation of the antenna is on when ones of the digital data signal are received.45.Page 41 of 5546.Attorney Docket No. 3153.148AWO 33. The method of claim 30, wherein the antenna system is configured so that radiation of the antenna is off when zeroes of the digital data signal are received.

34. The method of claim 30, wherein the antenna system is configured so that radiation of the antenna is on when ones of the digital data signal are received, wherein the antenna system is configured so that radiation of the antenna is off when zeroes of the digital data signal are received.

35. The method of claim 30, wherein the antenna is an antenna of an antenna array.

36. The method of claim 30, wherein the antenna is an antenna of a phased array of antennas.

37. The method of claim 30, wherein the antenna is an antenna of a phased array of antennas, and wherein the method includes controlling the phased array of antennas according to a beamforming algorithm.

38. The method of claim 30, wherein the antenna is an antenna of a phased array of antennas, wherein the antenna system is configured so that radiation of the antenna is on when ones of the digital data signal are received, wherein the antenna system is configured so that radiation of the antenna is off when zeroes of the digital data signal are received.

39. The method of claim 30, wherein the antenna system includes a diode responsive the digital data signal configured for turning on and off the radiation of the antenna, wherein the antenna is an antenna of a phased array of antennas, wherein the antenna system is configured so that radiation of the antenna is on when ones of the digital data signal are received, wherein the antenna system is configured so that radiation of the antenna is off when zeroes of the digital data signal are received.

40. An antenna system comprising:54.an antenna structure;55.a frequency selective surface disposed in a radiating path of the antenna structure;56.a feed network coupled to the antenna structure and configured to deliver a continuous- wave carrier signal thereto; and57.Page 42 of 5558.Attorney Docket No. 3153.148AWO a modulation control circuit configured to receive a baseband digital signal and to control a state of the frequency selective surface based on the baseband digital signal,59.wherein the antenna structure is energized with the continuous-wave carrier signal and radiates the carrier signal through the frequency selective surface when the frequency selective surface is in a transparent state,60.such that the emitted wave is modulated in accordance with the baseband digital signal.

41. An antenna system comprising:62.an antenna structure;63.a frequency selective surface disposed in a radiating path of the antenna structure; wherein the antenna system is configured to transmit a continuous-wave carrier signal to the antenna structure;64.wherein the antenna system is configured to control a state of the frequency selective surface in dependence on a baseband digital signal,65.wherein the antenna structure is energized with the continuous- wave carrier signal and radiates the carrier signal through the frequency selective surface when the frequency selective surface is in a transparent state so that an emitted wave emitted by the antenna system is modulated in accordance with the baseband digital signal.

42. The antenna system of claim 41, wherein the antenna structure comprises a single antenna element configured to radiate the continuous-wave carrier signal along a primary radiation axis.

43. The antenna system of claim 41, wherein the antenna structure comprises a phased array of antenna elements configured to cooperatively radiate the continuous-wave carrier signal with directional beam steering.

44. The antenna system of claim 41, wherein the frequency selective surface is a planar surface comprising a periodic array of conductive structures disposed on a dielectric substrate, each69.Page 43 of 5570.Attorney Docket No. 3153.148AWO structure electrically coupled to at least one active component configured to control electromagnetic transmission.

45. The antenna system of claim 41, wherein the frequency selective surface comprises a closed or partially enclosed shell structure surrounding at least a portion of the antenna structure, the shell structure configured to modulate directional transmission through at least one opening based on the state of the frequency selective surface.

46. The antenna system of claim 41, further comprising a feed network electrically coupled to the antenna structure and configured to deliver the continuous-wave carrier signal.

47. The antenna system of claim 41, wherein the feed network comprises a transmission line structure configured to provide an impedance-matched connection to an input impedance of the antenna structure.

48. The antenna system of claim 41, further comprising a modulation control circuit configured to receive the baseband digital signal and to generate a control waveform that transitions between two or more voltage levels, the control waveform being used to modulate the electromagnetic properties of the frequency selective surface.

49. The antenna system of claim 41, wherein the frequency selective surface comprises a plurality of embedded active elements including one or more PIN diodes or varactor diodes connected to switching bias lines.

50. The antenna system of claim 41, wherein the frequency selective surface is configured to support induced surface current in a conducting state and suppress induced current in a nonconducting state, thereby modulating the radiation of the continuous-wave carrier signal.

51. The antenna system of claim 41, wherein the frequency selective surface is configured such that its electromagnetic transparency is dynamically varied in real time based on the control waveform derived from the baseband digital signal.

52. The antenna system of claim 41, wherein the emitted wave comprises a digitally modulated carrier wave exhibiting on-off keying or amplitude modulation corresponding to a symbol stream derived from the baseband digital signal.79.Page 44 of 5580.Attorney Docket No. 3153.148AWO 53. The antenna system of claim 41 , wherein the frequency selective surface is fabricated using a low-loss dielectric substrate and a conductive metal layer etched to form subwavelength resonant elements.

54. The antenna system of claim 41, wherein the modulation control circuit comprises a digital logic controller or field-programmable gate array (FPGA) configured to synchronize the control waveform to a digital data stream.

55. The antenna system of claim 41, wherein transitions of the frequency selective surface are temporally aligned to about a maximum of stored near-field energy associated with the antenna structure.

56. The antenna system of claim 41, wherein the modulation control circuit is configured to generate a control waveform in dependence on the baseband digital signal such that state transitions of the frequency selective surface occur during a temporal window selected to minimize disruption of steady-state radiation from the antenna structure and to mitigate transient near-field energy effects.

57. The antenna system of claim 41, wherein timing of state transitions of the frequency selective surface is based on a synchronization signal associated with about a temporal peak of near-field energy accumulated by the antenna structure.

58. The antenna system of claim 41, wherein the modulation control circuit is configured to apply a control waveform to the frequency selective surface, the control waveform being temporally offset from the baseband digital signal in accordance with a delay profile calibrated to the geometry and feed characteristics of the antenna structure, such that state transitions of the frequency selective surface occur at about a maximum of stored near-field energy.

59. The antenna system of claim 41, wherein the modulation control circuit is configured to determine switching timing based on a calibrated timing profile derived from full-wave electromagnetic simulation of the antenna structure, the timing profile specifying control waveform transition points that reduce transient distortion by aligning switching events with about a temporal peak in stored near-field energy.

60. The antenna system of claim 41, wherein the synchronization between the baseband88.Page 45 of 5589.Attorney Docket No. 3153.148AWO digital signal and the conti nuous-wave carrier signal enables deterministic gating of the antenna structure's radiation through the frequency selective surface.

61. The antenna system of claim 41, wherein synchronization between the baseband digital signal and the continuous-wave carrier signal is configured to reduce electromagnetic ringing or overshoot associated with transient switching of the frequency selective surface.

62. An antenna system comprising:92.an antenna structure;93.a frequency selective surface disposed forward of the antenna structure;94.a feed network applying a carrier signal to the antenna structure, wherein the antenna structure radiates a continuous wave;95.a modulation control circuit receiving a baseband digital signal and controlling the frequency selective surface based on the baseband digital signal, wherein the antenna system emits a modulated carrier wave modulated by the baseband signal.

63. A method of designing and evaluating a modulated antenna system, comprising:97.establishing a simulation framework configured to simulate an antenna structure and a digital modulation input that modulates radiation characteristics of the antenna structure based on a digital signal.

64. The method of claim 63, wherein the antenna structure includes a phased array and the simulation framework is configured to model the phased array operating with a frequency selective surface (FSS) positioned in a near-field region.

65. The method of claim 63, further comprising simulating operation of the antenna structure with the FSS modulated between a radiating state and a non-radiating state based on a digital signal input.

66. The method of claim 63, wherein the FSS includes switching elements modeled to toggle between transparent and reflective electromagnetic states in response to a control signal derived Page 46 of 55101.Attorney Docket No. 3153.148AWO from the digital signal.

67. The method of claim 63, further comprising injecting a carrier signal into the antenna structure and recording electric field magnitude distributions during simulated modulation to evaluate near field behavior.

68. The method of claim 63, further comprising evaluating reactive energy accumulation in the near-field region of the antenna structure in response to modulated switching events of the FSS.

69. The method of claim 63, further comprising determining synchronization timing between the digital modulation signal and peak reactive near-field energy.

70. The method of claim 63, further comprising recording the time-domain response of the simulated system to identify radiated waveforms corresponding to a binary data sequence.

71. The method of claim 63, further comprising computing a spectral representation of the radiated signal and identifying sidebands corresponding to the baseband modulation frequency.

72. The method of claim 63, further comprising evaluating performance metrics from the simulation, including signal-to-noise ratio (SNR), bit error rate (BER), and spectral occupancy.

73. The method of claim 63, further comprising simulating a plurality of antenna system configurations, each varying in array geometry, switching frequency, or FSS topology, and identifying an optimized configuration based on simulation results.

74. The method of claim 63, further comprising selecting a final antenna system configuration based on trade-offs among modulation fidelity, bandwidth efficiency, and implementation complexity, and outputting the selected configuration for fabrication or deployment.

75. A method of designing a digitally modulated antenna system, comprising:111.establishing a full-wave electromagnetic simulation framework configured to model a phased array antenna structure in conjunction with a frequency selective surface (FSS) positioned in the near-field region of the antenna structure;112.injecting a carrier signal into the antenna structure through a feed network; and Page 47 of 55113.Attorney Docket No. 3153.148AWO simulating modulation of radiation based on a digital control signal applied to switching elements of the FSS to toggle between radiating and non-radiating states.

76. The method of claim 75, further comprising evaluating reactive energy accumulation in the near-field region during FSS-on states and suppression of far-field leakage during FSS-off states, wherein switching timing is synchronized with either peak reactive energy.

77. The method of claim 75, further comprising analyzing electric field distributions, radiated waveforms, and signal fidelity for transmitted binary data sequences represented by transitions between FSS transparency states.

78. The method of claim 75, further comprising computing the frequency-domain representation of radiated signals to evaluate sideband symmetry, spectral spread, and baseband-correlated bandwidth expansion.

79. The method of claim 75, further comprising extracting communication performance metrics from the simulation including bit error rate (BER), signal -to-noise ratio (SNR), and spectral occupancy as a function of baseband modulation frequency.

80. The method of claim 75, further comprising simulating multiple design variants differing in antenna array geometry, modulation rate, switching delay, and FSS topology, and comparing outputs to identify parameter combinations providing optimal bandwidth efficiency and modulation fidelity.

81. The method of claim 75, further comprising identifying degradation thresholds at which increasing the modulation rate results in loss of sideband strength or increased waveform distortion due to high-frequency spectral content.

82. The method of claim 75, further comprising selecting a finalized antenna system configuration from among the simulated variants based on a multi-metric optimization process and exporting configuration parameters for physical realization or deployment.

83. The method of claim 75, further comprising simulating signal-to-noise ratio (SNR) degradation at progressively increasing baseband modulation rates, wherein the full-wave simulation122.Page 48 of 55123.Attorney Docket No. 3153.148AWO framework modeled spectral dispersion and temporal misalignment induced by high-frequency switching of the FSS.

84. The method of claim 75, wherein the simulation framework was further configured to evaluate bit error rate (BER) performance based on an inverse relationship between SNR and BER, wherein BER was computed according to Equation (2), and wherein simulated data reflected exponentially worsening BER values at reduced SNR levels.

85. The method of claim 75, wherein the simulation framework was further configured to simulate BER as a function of both SNR and data rate, wherein higher data rates were modeled as reducing per-bit energy and producing elevated BER under equivalent SNR conditions.

86. The method of claim 75, wherein the FSS was simulated as a cylindrical structure surrounding an electrically small dipole antenna, and the simulation included comparison of radiation and input impedance profiles in both a transparent state and a reflective state of the FSS.

87. The method of claim 75, wherein the simulation framework was configured to evaluate near-field impedance and radiation suppression when the FSS was toggled to a high-reflectivity state approximating a perfect electric conductor (PEC).

88. The method of claim 76, wherein the user defined data includes a selected design frequency band, and wherein generating the plurality of candidate antenna structure configurations includes selecting, based on the selected design frequency band, a geometry template defining a spatial region layout for at least one variable antenna patch structure.

89. The method of claim 75, further comprising extending the modulation scheme modeled in the simulation framework beyond amplitude modulation to include at least one of frequency shift keying (FSK) or phase shift keying (PSK), and evaluating corresponding radiation and impedance performance.

90. A method comprising:131.inputting a carrier frequency into an antenna structure of an antenna system;132.inputting a digital data signal into a modulation control circuit of the antenna system, Page 49 of 55133.Attorney Docket No. 3153.148AWO wherein the antenna structure comprises a phased array of antennas,134.wherein the antenna system includes a frequency selective surface (FSS) disposed in a radiating path of the antenna structure and located in a near-field region of the antenna structure,135.wherein the FSS includes switching elements controlled by the modulation control circuit to toggle between a transparent state and a reflective state in dependence on the digital data signal,136.wherein the modulation control circuit is configured to initiate state transitions of the FSS at about time points corresponding to maxima in stored near-field energy of the antenna structure, based on a synchronization signal derived from the carrier frequency,137.wherein the antenna structure radiates a continuous wave independently of the digital data signal, and wherein modulation of the carrier signal is achieved by toggling the FSS to generate a time-domain modulated carrier wave corresponding to the digital data signal.

91. A method compri sing :139.inputting a carrier frequency into an antenna structure of an antenna system; inputting a digital data signal into a modulation control circuit of the antenna system,140.wherein the antenna structure comprises a phased array of antennas,141.wherein the antenna system includes a frequency selective surface (FSS) disposed in a radiating path of the antenna structure and located in a near-field region of the antenna structure,142.wherein the FSS includes switching elements controlled by the modulation control circuit to toggle between a transparent state and a reflective state in dependence on the digital data signal, wherein the modulation control circuit is configured to initiate state transitions of the FSS at about time points corresponding to maxima in stored near-field energy of the antenna structure, based on a synchronization signal derived from the carrier frequency,143.Page 50 of 55144.ttorney Docket No. 3153.148AWO wherein the antenna structure radiates a continuous wave independently of the digital data signal, and wherein modulation of the carrier signal is achieved by toggling the FSS to generate a time-domain modulated carrier wave corresponding to the digital data signal.

92. An antenna system comprising:146.an antenna structure comprising a phased array of radiating elements;147.a frequency selective surface (FSS) disposed in a near-field region in front of the antenna structure, the FSS including switching elements configured to toggle between transparent and reflective states;148.a modulation control circuit configured to:149.receive a baseband signal,150.control the switching elements of the FSS to modulate radiation of the antenna structure in dependence on binary values of the baseband signal such that radiation is enabled when the baseband signal corresponds to a first binary value and suppressed when the baseband signal corresponds to a second binary value,151.determine timing for toggling the FSS based on a synchronization signal derived from a carrier signal applied to the antenna structure, the synchronization signal being representative of energy buildup in the near-field region, and152.initiate state transitions of the FSS at about a temporal peak of stored near-field energy of the antenna structure153.wherein the antenna system is thereby configured to emit a time-domain modulated carrier wave corresponding to the baseband signal.

93. A method compri sing :155.inputting a carrier frequency into an antenna of an antenna system;156.inputting a digital data signal into the antenna,157.wherein the antenna is part of a phased array of antennas,158.wherein the antenna system includes a diode responsive to the digital data signal and configured to switch radiation of the antenna on and off,159.wherein radiation of the antenna is enabled when the digital data signal corresponds to a binary one and suppressed when the digital data signal corresponds to a binary zero, and160.wherein the phased array is controlled according to a beamforming algorithm.161.Page 51 of 55162.Attorney Docket No. 3153.148AWO 94. An antenna system comprising:163.an antenna structure configured to radiate a continuous-wave carrier signal;164.a frequency selective surface (FSS) disposed in a radiating path of the antenna structure and positioned in a near-field region, the FSS comprising a planar surface formed on a low-loss dielectric substrate and including a periodic array of subwavelength conductive structures, each structure electrically coupled to one or more active components comprising PIN diodes or varactor diodes connected to switching bias lines, the FSS being configured to support induced surface current in a conducting state and to suppress induced current in a non-conducting state; a feed network comprising a transmission line structure electrically coupled to the antenna structure and configured to deliver the continuous-wave carrier signal with impedance matching to the input impedance of the antenna structure;165.a modulation control circuit comprising a digital logic controller or field-programmable gate array (FPGA), the modulation control circuit being configured to:166.receive a baseband digital signal,167.generate a control waveform in dependence on the baseband digital signal, the control waveform transitioning between two or more voltage levels to dynamically vary electromagnetic transparency of the FSS in real time,168.calibrate timing of control waveform transitions using a delay profile or timing profile derived from full-wave electromagnetic simulation of the antenna structure,169.apply the control waveform to the FSS such that state transitions of the FSS occur at about a temporal peak of stored near-field energy of the antenna structure,170.synchronize the control waveform to the baseband digital signal and a synchronization signal derived from the continuous- wave carrier signal,171.and reduce transient distortion, electromagnetic ringing, or overshoot associated with switching by aligning state transitions with steady-state radiation conditions;172.wherein the antenna structure radiates the continuous-wave carrier signal through the FSS in the transparent state to emit a digitally modulated carrier wave exhibiting on-off keying or amplitude modulation corresponding to a symbol stream derived from the baseband digital signal.

95. A method of designing and evaluating a modulated antenna system, comprising:174.Page 52 of 55175.ttorney Docket No. 3153.148AWO establishing a simulation framework configured to simulate an antenna structure comprising a phased array of antenna elements in conjunction with a frequency selective surface (FSS) positioned in a nearfield region of the antenna structure;176.injecting a carrier signal into the antenna structure and simulating operation of the FSS in response to a digital modulation signal, the FSS including switching elements modeled to toggle between transparent and reflective electromagnetic states in accordance with a control signal derived from the digital modulation signal, thereby modulating radiation characteristics of the antenna structure between radiating and non-radiating states;177.recording electric field magnitude distributions during simulated modulation to evaluate near-field behavior, including accumulation of reactive energy in the near-field region and identifying timedomain responses corresponding to binary data sequences;178.determining synchronization timing between the digital modulation signal and peak reactive near-field energy to minimize transient energy buildup and optimize modulation stability;179.computing a spectral representation of the radiated signal to identify modulation sidebands and evaluating performance metrics including signal-to-noise ratio (SNR), bit error rate (BER), and spectral occupancy;180.simulating a plurality of antenna system configurations varying in phased array geometry, switching frequency, and FSS topology, and selecting an optimized configuration based on a trade-off analysis among modulation fidelity, bandwidth efficiency, and implementation complexity;181.and outputting the selected antenna system configuration for fabrication or deployment.

96. A method of designing a digitally modulated antenna system, comprising: establishing a full-wave electromagnetic simulation framework configured to model a phased array antenna structure in conjunction with a frequency selective surface (FSS) positioned in the near-field region of the antenna structure;183.injecting a carrier signal into the antenna structure through a feed network;184.simulating modulation of radiation by applying a digital control signal to switching elements of the FSS to toggle between radiating and non-radiating states;185.analyzing reactive energy accumulation in the near-field region during FSS-on states and suppression of far-field radiation during FSS-off states, with switching timing synchronized to about peak reactive energy levels;186.evaluating electric field distributions, radiated time-domain waveforms, and signal fidelity for binary Page 53 of 55187.Attorney Docket No. 3153.148AWO data sequences represented by transitions between FSS transparency states;188.computing a frequency-domain representation of radiated signals to evaluate sideband symmetry, spectral spread, and modulation-correlated bandwidth expansion;189.extracting communication performance metrics including bit error rate (BER), signal-to-noise ratio (SNR), and spectral occupancy as a function of baseband modulation frequency;190.simulating multiple design variants differing in array geometry, modulation rate, switching delay, and FSS topology, and identifying performance degradation thresholds at which increased modulation rate causes sideband attenuation or waveform distortion due to spectral dispersion;191.evaluating BER performance as a function of both SNR and data rate, wherein the framework models inverse SNR-BER relationships and elevated BER values at high data rates due to reduced per-bit energy;192.modeling the FSS as a cylindrical or conformal structure surrounding an electrically small dipole antenna, and comparing input impedance and radiation profiles across transparent and reflective FSS states, including a high-reflectivity state approximating a perfect electric conductor (PEC); extending the modulation scheme in the simulation to include frequency shift keying (FSK) or phase shift keying (PSK), and analyzing the resulting radiation and impedance characteristics;193.and selecting a final antenna system configuration based on a multi-metric optimization process balancing modulation fidelity, bandwidth efficiency, and implementation feasibility, and outputting the selected configuration for fabrication or deployment.194.Page 54 of 55195.Attorney Docket No. 3153.148AWO

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