A frequency reconfigurable on-chip multi-channel antenna

Abstract

This invention discloses a frequency-reconfigurable on-chip multi-channel antenna, belonging to the field of microwave and millimeter-wave antenna technology. The antenna is a single-layer passive structure, including a direct-feed excitation, a parallel-coupled feed line, a gradient traveling wave line, a uniform traveling wave line, and equidistantly arranged resonant radiating patches. Signals are introduced into multiple channels via electromagnetic coupling, and artificial surface plasmon structures are used to effectively suppress inter-channel crosstalk and enhance the local electric field. By filtering the wavelength of the externally fed signal, this antenna structure can operate in different center frequency bands (such as 140GHz and 220GHz). This antenna has advantages such as compact structure, convenient power supply, high directional gain, and good process compatibility, making it suitable for RF front-end systems requiring multi-band and high integration, such as 6G communication.

Description

Technical Field

[0001] This invention belongs to the field of microwave and millimeter-wave antenna technology, specifically relating to a frequency-reconfigurable on-chip multi-channel antenna. Background Technology

[0002] As wireless communication technology evolves towards 5G-Advanced and 6G, the available spectrum resources are constantly expanding to millimeter wave and even terahertz bands. In order to support multi-standard, multi-band communication and achieve high spectrum utilization, modern communication equipment (such as terminals and base stations) needs to integrate antenna systems capable of covering multiple discontinuous frequency bands within a limited physical space.

[0003] Currently, the mainstream technical solutions for realizing multi-band antenna functionality mainly fall into two categories: The first category is dual-band or multi-band antennas, which are implemented by designing a multi-resonant structure or loading parasitic elements on a single radiator, with each operating frequency band corresponding to an independent component. Although these antennas have a relatively simple structure, they typically have a large volume to increase the gain of a single frequency band and achieve isolation between independent components. The second category is frequency-reconfigurable antennas, which dynamically change the physical or electrical length of the antenna by integrating active adjustable components such as PIN diodes, varactors, or microelectromechanical systems (MEMS) switches, thereby achieving switching of operating frequency bands. Although these antennas have dynamic tuning capabilities, they introduce additional circuit complexity, DC power consumption, control links, and potential insertion losses, while also placing higher demands on manufacturing processes and system reliability.

[0004] Especially in the millimeter-wave band, where antenna size is extremely small, traditional frequency reconfiguration schemes based on discrete tunable components face a series of severe challenges, including high integration difficulty, limited tuning range, and significant parasitic effects. Therefore, there is an urgent need for a new type of antenna solution that can achieve "multi-band" or "quasi-reconfigurable" functions in a single structure with a more sophisticated physical design while maintaining the inherent advantages of passive structure simplicity and high reliability. This would allow for an elegant solution to the need for multi-band coverage within the limited space of the device. Summary of the Invention

[0005] This invention aims to solve the following problems existing in the prior art:

[0006] Traditional fixed multi-band antennas integrate antennas of different shapes by splicing them together, which faces the contradiction between limited equipment space and the need for multiple frequency bands. Designing a separate antenna for each frequency band would occupy valuable space and increase the size and weight of the equipment.

[0007] Integrating adjustable components such as PIN diodes and varactors into active frequency reconfigurable antennas introduces additional circuit complexity, DC power consumption, control costs, and reliability risks, especially in the millimeter-wave band where integration is particularly difficult.

[0008] Therefore, this invention provides an innovative on-chip multi-channel antenna structure. Its core objective is to enable the antenna to support at least two separate operating frequency bands through a precise fixed passive structure design without introducing any active tunable components. By utilizing the phase distribution differences naturally formed by signals at different operating frequencies in the structure, the antenna exhibits different radiation characteristics (such as beam pointing), thereby achieving a function similar to frequency reconfiguration. This achieves an excellent balance between structural simplification, high reliability, and functionality.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A frequency-reconfigurable on-chip multichannel antenna, which is a single-layer passive structure, includes:

[0011] A direct-feed excitation line, one end of which serves as the antenna feed port, and the other end is connected to a circular reflector.

[0012] Three parallel feed coupling lines are arranged parallel to one side of the direct feed excitation line and obtain signals from the direct feed excitation line through electromagnetic coupling, forming three independent signal transmission channels.

[0013] Each of the signal transmission channels is accompanied by a gradient traveling wave line, each of the gradient traveling wave lines including a transition section trunk and a plurality of stepped metal strips arranged therein with progressively decreasing lengths, for achieving a smooth impedance transformation and effectively suppressing electromagnetic crosstalk between channels.

[0014] A uniform traveling wave line is connected to each of the gradient traveling wave lines. Each of the uniform traveling wave lines includes a single wave band trunk and a plurality of uniformly sized radiating metal strips arranged thereal. The radiating metal strips together constitute an artificial surface plasmon structure for uniformly distributing energy and enhancing the local electric field near the uniform traveling wave line.

[0015] Multiple resonant radiating patches are arranged in an array at equal intervals and coupled to the radiating metal strips at the ends of the corresponding uniform traveling wave lines, for efficiently radiating signals into free space.

[0016] The physical structure and dimensional parameters of the direct-feed excitation line, circular reflector, fed parallel coupling line, gradient traveling wave line, and uniform traveling wave line are collaboratively designed and optimized to achieve efficient coupling between non-contact structures in both frequency bands, enabling the entire antenna structure to support at least two separate operating frequency bands. By changing the operating frequency of the input RF signal, a standing wave of the corresponding wavelength is formed on the direct-feed excitation line; the three consistent fed parallel coupling lines transmit the amplitude and phase information of this standing wave to the three channels through electromagnetic coupling; due to structural consistency, the three channels are simultaneously excited in all supported frequency bands, but a fixed phase shift is formed between the channels in different frequency bands; this phase shift is ultimately propagated to the radiating array composed of resonant radiating patches, causing the antenna to exhibit different radiation modes in different operating frequency bands.

[0017] Furthermore, the resonant radiation patch is preferably in the form of an open resonant ring, with a shaped frame on its periphery and limiting spokes inside, to facilitate oscillation initiation and stabilization of the resonant mode.

[0018] Furthermore, the dimensions of the circular reflector are optimized to adjust the standing wave distribution on the direct-feed excitation line, thereby achieving good impedance matching in different operating frequency bands.

[0019] Furthermore, the antenna operates on the principle that changes in the input signal frequency alter the wavelength of the standing wave on the direct-feed excitation line, thereby changing the relative phase relationship between the three parallel channels through electromagnetic coupling, ultimately resulting in a change in the radiation mode. This constitutes a passive frequency selection and radiation mode reconstruction method based on a fixed passive structure.

[0020] Compared with the prior art, the on-chip multi-channel antenna provided by the present invention has the following significant advantages:

[0021] 1. It adopts a completely passive fixed structure, which eliminates the need for DC bias circuits, control lines or adjustable components, thus fundamentally avoiding the power consumption, loss, nonlinearity and reliability problems caused by them. It has low structural complexity and high stability.

[0022] 2. Through a precisely designed fixed structure and frequency-related phase modulation mechanism, the radiation mode can be switched simply by changing the external excitation frequency. Functionally, it achieves a similar effect to "frequency reconstruction", but the implementation method is simpler and more reliable.

[0023] 3. The unique design combining gradient traveling wave lines with artificial surface plasmon structures effectively suppresses mutual interference between multiple channels, ensuring the independence of operation in each frequency band. Simultaneously, the conformally arranged radiating patch array of multiple channels facilitates the formation of highly directional, high-gain radiating beams.

[0024] 4. The entire antenna has a single-layer planar structure with small electrical size, making it very suitable for mainstream microwave and millimeter-wave integrated circuit processes such as silicon-based (Si), gallium arsenide (GaAs), or low-temperature co-fired ceramic (LTCC). It is easy to integrate with RF front-end chips on a single chip to achieve system miniaturization.

[0025] 5. The multi-channel design method described above can further expand the number of channels to support more operating frequency bands or form more complex beamforming arrays, demonstrating good design scalability. Attached Figure Description

[0026] To more clearly illustrate the technical solution and beneficial effects of the present invention, the accompanying drawings will be briefly described below. It should be understood that the following drawings are merely illustrative and do not constitute a limitation on the scope of protection of the present invention.

[0027] Figure 1 This is a schematic planar view of the overall structure of the on-chip multi-channel antenna provided in an embodiment of the present invention.

[0028] The diagram illustrates the layout and connections of the core components, with reference symbols indicating each part. Specifically, these include: direct-feed excitation line 1, fed parallel coupling line 2, gradient traveling wave line 3 (containing the transition section trunk line 3.1 and stepped metal strip 3.2), uniform traveling wave line 4 (containing the traveling wave section trunk line 4.1 and radiating metal strip 4.2), resonant radiating patch 5 (including the dihedral frame 5.1 and limiting spokes 5.2), and circular reflector 6. The diagram also shows the left channel 7, central channel, and right channel 8 naturally formed by this structure.

[0029] Figure 2 for Figure 1 The simulated return loss (S11 parameter) curve of the antenna structure shown is presented. This figure illustrates the impedance matching performance of the antenna in two target frequency bands (centered at 140 GHz and 220 GHz).

[0030] Figure 3 This is a schematic diagram of the near-field electric field distribution when the antenna of this invention operates at a frequency of 142 GHz.

[0031] Figure 4 This is a schematic diagram of the near-field electric field distribution when the antenna of this invention operates at a frequency of 224 GHz.

[0032] Figure 5 This is the far-field radiation pattern of the antenna of the present invention when it operates at a frequency of 142 GHz. The figure includes a side view and a top view, showing the three-dimensional radiation characteristics of the antenna in this frequency band, such as beam directivity and gain.

[0033] Figure 6 This is the far-field radiation pattern of the antenna of the present invention when it operates at a frequency of 224 GHz. The diagram includes a side view and a top view for comparison with... Figure 5 The comparison shows that the antenna can form a stable directional radiation beam in different operating frequency bands. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0035] Example 1:

[0036] This embodiment provides an on-chip multi-channel antenna, the overall structure of which is shown in the planar diagram below. Figure 1 As shown, this antenna is a single-layer metal (e.g., gold) structure fabricated on a gallium arsenide (GaAs) substrate. It is prepared using standard integrated circuit photolithography and deposition processes, and is fully compatible with mainstream microwave and millimeter-wave integrated circuit fabrication processes such as III-V compound, CMOS, and LTCC, facilitating monolithic integration with the RF front-end.

[0037] 1. Overall structure and signal path

[0038] like Figure 1 As shown, the core structure of the antenna is symmetrically arranged along the centerline. The radio frequency (RF) signal is fed from the left end of the direct-feed excitation line 1 (the pads or coplanar waveguide transition are not shown in the figure). The right end of the direct-feed excitation line 1 terminates at a circular reflector 6, which is used to adjust the standing wave distribution on the feed line. On the same side of the direct-feed excitation line 1, three parallel feed-coupled lines 2 are placed at a certain spacing (less than 10 μm). In this invention, when the feed frequency is in the 140 GHz and 220 GHz bands, the ratio of the standing wave wavelength formed on the direct-feed excitation line 1 to the length of the parallel feed-coupled lines 2 is approximately 3:1 and 2:1, respectively. Through edge coupling effect, RF energy is coupled from the direct-feed excitation line 1 to the parallel feed-coupled lines 2, thus naturally forming three independent and structurally identical signal transmission channels (left channel 7, right channel 8, and the central channel is unlabeled in the figure). Adjusting and optimizing the spacing between the direct-feed excitation line 1 and the fed parallel coupling line 2, as well as the distance between the three fed parallel coupling lines 2, can improve the coupling efficiency.

[0039] 2. Specific features of each component

[0040] Gradient Traveling Wave Line 3: The input of each gradient traveling wave line 3 is connected to the output of the corresponding fed parallel coupling line 2. Each gradient traveling wave line 3 consists of a transition trunk line 3.1 and multiple stepped metal strips 3.2 attached to one side of it. The length of these stepped metal strips 3.2 decreases linearly stepwise along the signal transmission direction (from the coupling end to the radiating end). This design achieves broadband impedance gradient matching from the coupling line to the subsequent radiating structure. At the same time, the stepped edges effectively disrupt the propagation path of surface waves between channels, significantly reducing mutual coupling and crosstalk between the left, middle, and right channels.

[0041] Uniform traveling wave line 4: The end of the gradient traveling wave line 3 smoothly transitions to the uniform traveling wave line 4. Each uniform traveling wave line 4 consists of a traveling wave trunk line 4.1 and multiple radiating metal strips 4.2 of identical size arranged uniformly along it. These radiating metal strips 4.2 serve as the unit of the artificial surface plasmon polariton (SSPP) structure, effectively confining and transmitting high-frequency signals and concentrating energy at the ends of the strips to form a strong local electric field, creating conditions for efficient radiation.

[0042] Resonant radiating patch 5: The arrangement period of the resonant radiating patch 5 corresponds to three radiating metal strips 4.2, that is, every three consecutive radiating metal strips 4.2 are coupled to one resonant radiating patch 5. In this embodiment, the resonant radiating patch 5 adopts the form of an open resonant ring (SRR). The opening direction of the open resonant ring faces the uniform traveling wave line 4. Each SRR is surrounded by a dihedral frame 5.1, and a limiting spoke 5.2 is connected inside. This design makes it easy to excite a stable magnetic resonance mode, and its resonant frequency can be finely controlled by the size of the ring, the size of the opening, and the internal structure. All the resonant radiating patches 5 are arranged in a row at equal intervals to form a linear radiating array.

[0043] Circular reflector 6: Its diameter has been optimized through simulation to ensure that, within the target frequency band, the reflection phase on the direct-feed excitation line 1 is conducive to energy efficient coupling to the feed parallel coupling line 2 on the same side.

[0044] Key design dimensional relationships: The spacing (s) between the fed parallel coupling line 2 and the direct-feed excitation line 1 is designed based on the center frequency (f) of the target frequency band and the required coupling strength, and typically meets the following requirements: ,in The wavelength of the signal guided in the medium is denoted by 4.2. Since the radiating metal strip 4.2 effectively confines the electromagnetic energy within the wavelength range, the resonant radiating patch 5 is positioned as close as possible to the radiating metal strip 4.2. The length, width, and adjacent spacing of the radiating metal strip 4.2 primarily determine the slow-wave characteristics of the uniform traveling wave line 4, affecting the feeding efficiency of the resonant radiating patch 5. This synergistic optimization of dimensional relationships is fundamental to ensuring that different channels operate within a predetermined frequency band.

[0045] 3. Working principle and frequency band selection

[0046] The key innovation of this invention lies in optimizing the structural dimensions of the three consistent left, center, and right channels (from the coupling line to the radiating patch) to support different center resonant frequencies. Unlike previous dual-band antennas, this invention does not combine multiple antenna types but rather forms a complete and unified signal path. By changing the frequency of the RF signal input to the direct-feed excitation line 1, the standing wave wavelength changes accordingly. The three parallel-coupled feed lines 2 simultaneously couple energy from the direct-feed excitation line 1, but due to different standing wave distributions, a specific fixed phase difference is formed between the signals coupled to the three channels (e.g., approximately 2π / 3 in the 140GHz band and approximately π in the 220GHz band). This phase difference, after transmission, acts on the radiating array, ultimately causing the antenna to exhibit different radiation modes at different frequency bands. This approach achieves functional frequency band selection while maintaining the passive and highly reliable nature of the antenna itself.

[0047] 4. Performance Verification

[0048] To verify the performance of the antenna in this embodiment, a full-wave electromagnetic simulation was performed. Figure 2 The simulated return loss (S11) curve of the antenna is shown. It can be seen that there are two obvious resonance valleys in the 120-240GHz frequency band. The center of the first resonance valley is located at approximately 142GHz; the center of the second resonance valley is located at approximately 224GHz.

[0049] like Figure 3 The diagram shows the near-field electric field of a frequency-reconfigurable on-chip multichannel antenna at 142 GHz. In the three signal transmission channels—left channel 7, central channel, and right channel 8—the electric field is simultaneously excited, with very similar amplitudes and a 2π / 3 phase difference between adjacent channels.

[0050] like Figure 4 The figure shows a schematic diagram of the near-field electric field of a frequency-reconfigurable on-chip multichannel antenna at 224 GHz. The three signal transmission channels are simultaneously excited, and the electric field amplitudes are similar, but there is a phase difference of π between adjacent channels.

[0051] Figure 5 and Figure 6 The far-field radiation patterns of the antenna at two frequency points are shown (including side and top views). Simulation results show that the antenna can generate stable directional radiation beams at 142 GHz and 224 GHz, with the maximum radiation direction perpendicular to the antenna plane, and the directional gains reaching over 3.6 dBi and 5.4 dBi, respectively, demonstrating good radiation characteristics.

[0052] Example 2:

[0053] Based on Example 1, the number of fed parallel coupling lines 2 and their corresponding channels can be further increased. For example, more independent radiation channels can be designed to form a narrower, higher-gain beam.

[0054] Example 3:

[0055] Based on Embodiments 1 and 2, differentiated design of the channel's structural parameters allows the antenna to use different channels in different operating frequency bands, or to change the far-field performance of a channel within any operating frequency band, further expanding multi-frequency applications and diverse radiation modes. This demonstrates the excellent scalability of the invention's design framework.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A frequency reconfigurable on-chip multi-channel antenna, characterized in that, It is a single-layer passive structure, including: A direct-feed excitation line (1) has one end serving as the antenna feed port and the other end connected to the circular reflector (6). Three parallel feed coupling lines (2) are arranged in parallel on one side of the direct feed excitation line (1) and obtain signals from the direct feed excitation line (1) through electromagnetic coupling, serving as the starting point of three identical signal transmission channels; The input ends of the three tapered traveling wave lines (3) are respectively connected to the output ends of the corresponding fed parallel coupling lines (2), corresponding to each of the signal transmission channels. Each tapered traveling wave line (3) includes a transition section trunk line (3.1) and multiple stepped metal strips (3.2) arranged along it with progressively decreasing lengths, used to achieve impedance transformation and isolation between channels. A uniform traveling wave line (4) is connected to the output end of each of the gradient traveling wave lines (3). Each of the uniform traveling wave lines (4) includes a single waveband trunk line (4.1) and a plurality of uniformly sized radiating metal strips (4.2) arranged along it. The radiating metal strips (4.2) constitute an artificial surface plasmon structure. Multiple resonant radiation patches (5) are arranged at equal intervals and coupled to the radiation metal strips (4.2) on both sides of the uniform traveling wave line (4); the resonant radiation patch (5) is an open resonant ring structure, with a two-shaped frame (5.1) on its outer contour and a limiting spoke (5.2) inside, and the opening direction of the open resonant ring is towards the uniform traveling wave line (4). The structure and dimensions of the direct-feed excitation line (1), circular reflector (6), fed parallel coupling line (2), gradient traveling wave line (3), uniform traveling wave line (4) and resonant radiation patch (5) are configured in a coordinated manner so that the antenna structure can support at least two separate operating frequency bands.

2. The on-chip multi-channel antenna according to claim 1, wherein, The at least two separate operating frequency bands include a first frequency band centered at 140 GHz and a second frequency band centered at 220 GHz.

3. The on-chip multi-channel antenna of claim 1, wherein, The size of the circular reflector (6) is configured to adjust the standing wave distribution on the direct-feed excitation line (1) to achieve broadband impedance matching in different operating frequency bands.

4. The on-chip multi-channel antenna of claim 1, wherein, The length of the stepped metal strip (3.2) decreases step by step along the signal transmission direction of the gradient traveling wave line (3), and its decreasing gradient is used to realize the impedance transformation of the gradient traveling wave line (3); the length of the radiating metal strip (4.2) is used to adjust the slow wave characteristics of the uniform traveling wave line (4).

5. A communication device, characterized by It includes an on-chip multichannel antenna as described in any one of claims 1 to 4.

6. An antenna frequency selection method applied to the on-chip multi-channel antenna according to any one of claims 1 to 4, characterized in that, By changing the operating frequency of the radio frequency signal input to the direct feed excitation line (1), the three signal transmission channels in the antenna structure are simultaneously excited, and different fixed phase differences are formed between the three signal transmission channels at different operating frequencies. The fixed phase difference is transmitted to the radiation array composed of the resonant radiation patch (5), so that the antenna presents different radiation modes at different operating frequency bands.

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