Active Vivaldi Antenna

Abstract

An antenna system having: a Vivaldi antenna configured to impedance match with an antenna impedance Za at and above a frequency fc but not below the frequency fc; a field effect transistor buffer coupled to the Vivaldi antenna, the length of the coupling between the antenna terminals and the buffer having a distance much smaller than the wavelength at the frequency fc, the buffer being configured to present a high impedance at frequencies substantially < fc, and the buffer output impedance also being configured to match the system impedance Z0 at frequencies both above and below fc.

Description

[0001] [Cross-reference to related applications]

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 62 / 734,881, filed on September 21, 2018, and entitled “Active Vivaldi Antenna,” the disclosure of which is hereby incorporated by reference.

[0003] This application also relates to U.S. Provisional Patent Application Serial No. 62 / 734,885, filed on September 21, 2018 and entitled “Active Wideband Antenna,” and its related PCT International Application Serial No. ____, filed on the same day as this application and entitled “ActiveWideband Antenna” (Agent Case No. 631584-3), the disclosures of which are hereby incorporated by reference. [Technical field]

[0004] Active Vivaldi Antenna [Background technology]

[0005] Passive Vivaldi antennas typically have a bandwidth of about 10:1 and require large size to operate well at low frequencies. For example, see Lee et al., "A low profile wide-band (5:1) dual-pol array," IEEE AWPL, Vol. 2, 2003, and JJ Lee and S. Livingston, "Wide band bunny-ear radiating element," Proceedings of IEEE Antennas and Propagation Society International Symposium, Ann Arbor, MI, USA, 1993, pp. 1604-1607, Vol. 3. Active monopole and dipole antennas use buffer amplifiers, but they only operate up to about the first resonance of the dipole antenna. Therefore, their high-frequency bandwidth is limited. [Summary of the invention]

[0006] In one aspect, the present invention provides a broadband Vivaldi-type receiving antenna that operates in a "traditional band" of operation (where the dimension is >= 1 / 2 wavelength (λ) at the minimum frequency) and a low-frequency "extended band" (where the dimension is <λ / 2). The active Vivaldi of the present invention includes a Vivaldi antenna with a balanced feed (one example is a rabbit ear antenna) and a differential buffer amplifier directly integrated into each feed point of the Vivaldi antenna. "Integrated directly into each feed" means that any transmission line used to connect the arms of the antenna to the buffer is as short as possible, and the length must be less than a quarter wavelength for any frequency in the extended band, and the length is preferably less than 1 / 10 wavelength for any frequency in the extended band. With such short lengths, there is no room for an impedance matching device (such as a balanced-unbalanced transformer) between the antenna feed point and the differential buffer amplifier, nor is there any desired space. Instead, each differential buffer amplifier is preferably configured to have a high impedance input in the extended band (i.e., much higher than the antenna impedance in the traditional band). In some embodiments, the input impedance of the buffer amplifier is also higher in the traditional frequency band, while in other embodiments, the buffer amplifier is preferably matched to the antenna impedance in the traditional frequency band by using a feedback circuit. The buffers each preferably include one or more FETs, and more preferably include one or more gallium nitride (GaN) FETs, and the buffers can be arranged with differential or single-ended outputs. The output of the buffer is impedance matched to the interface impedance (typically 50, 75 or 100 ohms) both in the traditional frequency band and the extended frequency band.

[0007] On the other hand, the present invention provides a receive antenna having a wider bandwidth than is possible with prior art antennas without increasing its size. Conventional Vivaldi antennas operate over a 10:1 bandwidth and are between 0.5λ and 1λ in size at the minimum frequency. For example, antennas operating at 1-10 GHz are ~6 inches or larger in size. Increasing the bandwidth requirement to 0.1-10 GHz would mean increasing the size to ~60 inches (and would introduce additional design challenges to maintain impedance matching), or would force the user to accept severely degraded receive sensitivity (i.e., minimum detectable signal) over the 0.1-1 GHz extended band. The present invention can allow operation at 0.1-10 GHz for a 6 inch size without severely degrading sensitivity.

[0008] In yet another aspect, the present invention provides a Vivaldi antenna configured to impedance match an antenna impedance Za (typically a real impedance) at and above a frequency fc but not below a frequency fc (at frequencies much lower than fc, the Vivaldi antenna preferably has a reactive impedance whose absolute value is typically greater than Za); a field effect transistor buffer is coupled to the Vivaldi antenna, the length of the coupling between the antenna terminal and the buffer being a distance much smaller than the wavelength at the frequency fc, the buffer being configured to present a high input impedance at a frequency substantially <fc, and the buffer output impedance being further configured to match the system impedance Z0 at frequencies both above and below fc, where fc is the frequency defining the boundary between the extended frequency band and the traditional frequency band.

[0009] In yet another aspect, the present invention provides a Vivaldi antenna system having: a pair of antenna arms of a Vivaldi-shaped antenna, the antenna arms diverging from each other as they radiate from a proximal end at the antenna throat; a buffer amplifier comprising at least a pair of transistorized amplifiers, the buffer amplifier being embodied in an IC chip and the IC chip being bonded directly to the proximal ends of the antenna arms at the antenna throat, whereby a control electrode of each of the pair of transistorized amplifiers is arranged to be less than one quarter of the wavelength of the highest frequency in an energy spreading band occurring in the Vivaldi antenna system from the proximal ends of the antenna arms.

[0010] On the other hand, the present invention provides a Vivaldi antenna system, which includes: a Vivaldi type receiving antenna, which operates in a "traditional frequency band" of operation (wherein the size of the Vivaldi type receiving antenna is >= 1 / 2 wavelength (λ) at the minimum frequency in the "traditional frequency band" of operation) and a low-frequency "extended frequency band" (wherein the size of the Vivaldi type receiving antenna is <λ / 2); a buffer amplifier, which has at least one pair of FET amplifiers, each of the pair of FET amplifiers having a gate (or gate electrode) directly coupled to an arm of the Vivaldi type receiving antenna, each of the pair of FET amplifiers having an input impedance much higher than the characteristic impedance of the Vivaldi type receiving antenna in the extended frequency band.

Brief Description of the Drawings

[0011] FIGS. 1a and 1b depict a Vivaldi antenna according to the prior art ( FIG. 1a ) and according to the present disclosure ( FIG. 1b ).

[0012] Figure 2 shows one possible size of a prior art passive Vivaldi antenna, and Figure 2-1 and Figure 2-2 Shows Figure 2 0 is a simulation of a passive Vivaldi antenna, and the boundary frequency fc between the above-mentioned extended frequency band and the traditional frequency band is also shown.

[0013] Figure 3 A modified Vivaldi antenna is shown having buffer amplifiers on an IC chip, the amplifiers being placed as close as reasonably possible to the proximal ends of the arms of the Vivaldi antenna.

[0014] Figure 3-1 Depicted is a cross-sectional view of a FET of a buffer amplifier disposed in close proximity to the proximal end of an arm of a Vivaldi antenna in accordance with one embodiment of the disclosed technology.

[0015] Figure 3(a) to Figure 3(d) Simplified schematic diagrams of four implementations of GaN buffer amplifiers are depicted (the biasing networks of the buffer amplifiers are not shown). Figure 3 (a) and Figure 3 (b) has high impedance input and no feedback; Figure 3 (c) and Figure 3 (d) A high-pass feedback circuit comprising a capacitor C and a resistor R is incorporated to provide an input impedance that is high impedance in the low-frequency extended band and matches the antenna impedance in the high-frequency conventional band. Figure 3 (a) and Figure 3 (c) has a differential output, while Figure 3 (b) and Figure 3 (d) Transformer coupling (via transformer T) is used to provide a single-ended output. Figure 3 (d) depicts a currently preferred embodiment.

[0016] Figure 4 A model used to simulate the effect of a GaN buffer on receive sensitivity is shown. A full wave simulation of the antenna is used to compose a 2-port S-parameter model that is directly used in a circuit simulator.

[0017] Figure 5(a) to Figure 5(c) Plotted is a simulation comparison of an active Vivaldi (with RC feedback) versus a passive Vivaldi. S21 (see Figure 5(a)) is the ratio of the antenna gain (including any amplifier gain and 5dB loss of the attenuator) to the antenna directivity. The reference plane for the noise figure (see Figure 5(b)) is the incident wave. The reference plane for the reflectivity (see Figure 5(c)) is the antenna terminals for the passive case and the buffer output for the active case. Note: 1 / f noise is not included in the model.

[0018] Figure 6(a) to Figure 6(c)A simulation comparison of gain, noise, and linearity (input 3rd order intercept point, reference plane is incident wave) with and without feedback in a buffer amplifier is shown. Feedback slightly degrades gain and NF, but reduces ripple and improves linearity. Note: 1 / f noise is not included in the model. [Specific implementation method]

[0019] The following description is proposed to enable those of ordinary skill in the art to carry out and use the present invention, and to incorporate the present invention in the context of a particular application. Various modifications and various uses in different applications will be easily clear to those skilled in the art, and the general principles defined herein can be applied to a wide range of embodiments. Thus, the present invention is not intended to be limited to the proposed embodiments, but to conform to the widest range consistent with the principles and novel features disclosed herein.

[0020] In the following detailed description, in order to provide a more thorough understanding of the present invention, a large number of specific details are set forth. However, it will be apparent to those skilled in the art that the present invention can be practiced without being limited to these specific details. In other cases, in order to avoid obscuring the present invention, well-known structures and devices are shown in block diagram form rather than in detail.

[0021] The reader's attention is directed to (i) all documents and documents filed concurrently with this specification, which are open to public inspection with this specification (the contents of all such documents and documents are incorporated herein by reference) and (ii) all documents and documents that are otherwise incorporated herein by reference (but not physically filed with this specification).

[0022] All features disclosed in this specification (including any attached claims, abstracts and drawings) may be replaced by alternative features for the same, equivalent or similar purposes, unless otherwise explicitly stated. Thus, unless otherwise explicitly stated, each feature disclosed is only an example of a general series of equivalent or similar features.

[0023] Furthermore, any element in a claim that does not explicitly recite a "means" for performing a specified function or a "step" for performing a specified function is not to be construed as a "means" or "step" clause as specified in 35 U.S.C. § 112(f). Specifically, the use of "step" or "act" in the claims herein is not intended to invoke the provisions of 35 U.S.C. § 112(f).

[0024] FIG. 1a shows a Vivaldi antenna according to the prior art, while FIG. 1b and FIG. Figure 3FIG. 1 shows an active Vivaldi antenna according to an embodiment of the present invention. In the prior art, a passive Vivaldi antenna may have a microstrip or stripline feeder (as shown in FIG. 1a ) or may have a “rabbit ear” shape or configuration (see the Vivaldi antenna 10 of FIG. 1b ). The Vivaldi antenna 10 has a pair of arms, each of which is Figure 3 The invention is different from the prior art in that, as shown in FIG1b and FIG10 , the antenna is provided with a power supply 10 at the throat region of the antenna. Figure 3 As shown, the FET buffer amplifier 12 is integrated directly onto or at the antenna feed 10P of the balanced arm 10 of the Vivaldi antenna.

[0025] For Figure 2 A prior art Vivaldi antenna of the dimensions shown, Figure 2-1 and Figure 2-2 The simulated performance of the Vivaldi antenna according to the prior art is shown in FIG. 1-3 GHz, the antenna is well matched to 150 ohms (see Figure 2-2 ), and the overall efficiency is close to 0dB (see Figure 2-1 ). This performance could potentially extend all the way to 10 GHz or more, but due to resource limitations, the simulations terminated at 3 GHz. Below 1 GHz, the impedance match degrades and the overall efficiency drops by 40 dB / decade. Between 200 MHz and 1 GHz, the impedance varies between series and parallel resonance. However, between 20 and 200 MHz, the impedance behaves as a small capacitor, similar to a short dipole. We consider this band to be the "short dipole" band, while 200 MHz to 1 GHz is the "transition" band for this antenna. The "short dipole" band and the "transition" band together form the "extended" band.

[0026] In the prior art, Figure 2 The Vivaldi antenna is considered unusable in the transition and short dipole bands (collectively referred to as the "extended band") due to its widely fluctuating impedance, and therefore its use will be limited to the conventional bands where S11 is less than -8 dB. On the other hand, by utilizing and positioning the buffer amplifier 12 as disclosed herein, Figure 3 An active Vivaldi antenna can be used for transition (and preferably also for extending the frequency band).

[0027] Figure 3(a) to Figure 3(d) Four possible implementations of the buffer amplifier 12 are shown in FIG. Figure 3(a)), the buffer amplifier 12 includes a pair of differential common source amplifiers, each of which is directly coupled to a balanced feed terminal of the Vivaldi antenna. This connection can be made using a transmission line that matches the antenna impedance in the traditional frequency band, but can also be made using another arrangement of two conductors (e.g., wires or traces that are not arranged in a traditional transmission line). The length d of this connection between the antenna terminal and the FET in the buffer 12 should be << the wavelength at the highest frequency of the extended frequency band (1 GHz in this example..., see Figure 2-2 ). The sources of the two transistors are connected to a common ground node and the differential output is taken to a receiver, or optionally, a second amplifier stage (not shown). A modification to this embodiment provides a single-ended output with the aid of a transformer ( Figure 3 (b)).

[0028] A preferred embodiment of the buffer amplifier 12 (see Figure 3 (c) and Figure 3 (d)) incorporates a feedback network including a resistor R and a capacitor C to achieve a buffer with high input impedance in the extended frequency band and matching the antenna impedance in the traditional frequency band. The output impedance of amplifier 12 is preferably set to the system impedance (Z0), which in many embodiments may be well equal to 50 ohms. In one embodiment, the high pass network ( Figure 3 (c) and Figure 3 The buffer amplifier 12 is shown in dashed lines in (d) and consists of a resistor R in series with a capacitor C (500 ohms and 2 pF in one example or implementation) that couples the drain D of the FET to the gate G. The goal is to design the buffer amplifier 12 so that above the RC cutoff frequency of the feedback network, both the input impedance and the optimum noise impedance are close to the antenna impedance. A second goal is to design the RC cutoff frequency so that feedback is minimized in the extended frequency band while maintaining amplifier stability and a relatively high input impedance compared to the antenna impedance in the extended frequency band.

[0029] The arms 10 of the Vivaldi antenna may be defined by metal on a printed circuit board or other dielectric substrate 15, such as Figure 3 and Figure 3-1 As shown, and includes a buffer amplifier 12 (preferably having at least two FET buffer amplifiers, such as Figure 3(a) to Figure 3(d)The IC chip 16 of the Vivaldi antenna (as depicted) is arranged on the substrate 15 so that the contact C of the chip 16 is directly bonded at the feeding point at the proximal end 10P of the arm 10 of the Vivaldi antenna and is arranged very close to the gate G of the FET amplifier in the buffer amplifier 12. The transmission line, which may be formed by, for example, a via of length d between the feeding point (at the contact C) arranged at the end 10P of the arm 10 of the Vivaldi antenna and the gate G, is preferably maintained as short as reasonably possible by forming the gate G of the FET amplifier adjacent to the aforementioned chip contact C. Figure 3-1 The cross-sectional view in shows one FET device with a vertical metal via coupling the metal gate G of the FET to the proximal end 10P of one arm 10 of the Vivaldi antenna at contact C. A second FET would be similarly arranged relative to the other arm 10 of the Vivaldi antenna. Figure 3(a) to Figure 3(d) as well as Figure 3-1 The distance d shown should be as short as possible and the proximal end (or feed point) 10P of the arm 10 of the Vivaldi antenna is preferably coupled immediately at the contact C. If the FET amplifier has more than one stage, the gate G of the first stage is preferably arranged close to the aforementioned contact C.

[0030] The length d of the transmission line (which may be embodied by a via, for example) is much smaller than the wavelength at frequency fc, and is preferably as short as reasonably possible.

[0031] Initial simulations of this technique were done using full wave simulations of the Vivaldi radiator and nonlinear models provided by the manufacturer of the transistor device. These models do have limitations in that they do not account for 1 / f noise, which can limit the fidelity of the results at the lowest frequencies. The first step is to convert the radiation pattern and impedance of the simulated radiator and generate a 2-port model of the antenna (see Figure 4 ). In this model, S21 is the total antenna efficiency (including impedance matching and radiation efficiency), while S22 is the passive antenna reflection coefficient. S21 and noise figure are evaluated both with and without the buffer. To evaluate the impact on sensitivity, 5dB attenuators are inserted after both antennas to account for receiver noise. Harmonic balance is also used to simulate the input third order intercept point (IIP3). The reference plane is the incident wave. The results of these preliminary simulations are shown in Figures 5(a) to 6(c) Presented in.

[0032] Go to Figure 5(a) to Figure 5(c), the active Vivaldi antenna with a buffer amplifier improves the antenna gain by >20dB at 20MHz compared to the passive Vivaldi antenna with a roll-off of 40dB / decade (see Figure 5(a)). The active Vivaldi antenna only rolls off at 20dB / decade. The improvement in noise figure (NF) (see Figure 5(b)) is almost equal to the gain improvement, but slightly lower. The reason for this is that the buffer has an internal noise source. Finally, the buffer output impedance is matched to 100 ohms (differential) with a reflectivity of <-10dB over almost the entire frequency band, while the passive antenna is matched only in the traditional band (see Figure 5(c)).

[0033] Figure 6(a) to Figure 6(c) shows a buffer amplifier with RC feedback (see Figure 3c and Figure 3d ) relative to no feedback (see Figure 3a and Figure 3b ) of a transistorized amplifier. Without feedback, there is considerable ripple in the transition band, which results in degraded linearity (see Figure 6(a)). Incorporating feedback degrades gain and NF very slightly (see Figure 6(b)), but significantly reduces ripple, which in turn removes the drop in IIP3 (see Figure 6(c)). Therefore, RC feedback is preferred for buffer amplifiers.

[0034] The FET devices in the buffer amplifier are preferably embodied as GaN devices, although other III-V devices or even silicon devices may be used when desired by one practicing the disclosed technique.

[0035] Having now described the invention in accordance with the requirements of the patent statutes, those skilled in the art will understand how to change and modify the invention to meet their specific requirements or conditions. Such changes and modifications can be made without departing from the scope and spirit of the invention as disclosed herein.

[0036] For illustration and disclosure, in accordance with legal requirements, the foregoing detailed description of exemplary and preferred embodiments is presented. It is not intended to be exhaustive nor to limit the invention to the precise forms described, but rather to enable other persons skilled in the art to understand how the invention is adapted to a particular use or implementation. The possibility of modifications and variations will be apparent to those skilled in the art. The description of exemplary embodiments is not intended to be limiting, and these embodiments may already include tolerances, feature sizes, specific operating conditions, engineering specifications, etc., and may vary between implementations or with changes in the prior art, and no limitation should be implied therefrom. The applicant has made this disclosure with respect to the current state of the art, but also anticipates advancements, and future adaptations may take these advancements into account, i.e., in accordance with the current state of the art at that time. If applicable, the scope of the invention is intended to be defined by the written claims and equivalents. Reference to an element in the singular form of a claim is not intended to mean "one and only one" unless expressly so stated. Moreover, whether an element, component, method, or process step in this disclosure is expressly recited in the claims or not, such element, component, or step is not intended to be dedicated to the public. No claim element herein is to be construed under the provisions of 35 U.S.C. § 2 as it existed on the date of filing of this application, unless the element is expressly recited using the phrase "means for...", and no method or process step herein is to be construed under these provisions unless the step is expressly recited using the phrase "comprising the step...".

[0037] Modifications, additions, or omissions may be made to the systems, devices, and methods described herein without departing from the scope of the invention. Components of the systems and devices may be integrated or separated. Moreover, the operations of the systems and devices may be performed by more, fewer, or other components. The methods may include more, fewer, or other steps. Additionally, the steps may be performed in any suitable order. As used in this document, "each" refers to each member of a set or each member of a subset of a set.

[0038] The concepts of the present invention include:

[0039] 1. A device, comprising: a Vivaldi antenna configured to impedance-match with an antenna impedance Za at and above a frequency fc but not below the frequency fc; a field-effect transistor buffer coupled to a terminal of the Vivaldi antenna, the length of the coupling between the antenna terminal and the field-effect transistor buffer being a distance much smaller than the wavelength at the frequency fc, the buffer being configured to present a high input impedance at a frequency substantially <fc, and the buffer output impedance being further configured to match with a system impedance Z0 at frequencies both above and below fc.

[0040] 2. The device of concept 1, wherein the buffer comprises a GaN FET.

[0041] 3. The apparatus of concept 1 or 2, wherein the antenna has a balanced feed and the buffer has a balanced input.

[0042] 4. The device of any one of concepts 1 to 3, wherein the buffer has differential outputs.

[0043] 5. The device of any one of concepts 1-3, wherein the buffer has a single-ended output.

[0044] 6. The apparatus of any one of concepts 1 to 5, wherein the buffer has a high impedance input in an extended band where the size of the Vivaldi antenna is < 1 / 2 wavelength (λ) at a minimum frequency, and is impedance matched to Za in a traditional band where the size of the Vivaldi antenna is >= 1 / 2 wavelength (λ) at the minimum frequency.

[0045] 7. The apparatus of any one of concepts 1 to 6, wherein the buffer comprises an RC high pass feedback network.

[0046] 8. A Vivaldi antenna system having: a pair of antenna arms of a Vivaldi-shaped antenna, the antenna arms diverging from each other as they radiate from a proximal end at the antenna throat; a buffer amplifier, the buffer amplifier comprising at least a pair of transistorized amplifiers, the buffer amplifier being embodied in an IC chip and the IC chip being bonded directly to the proximal ends of the antenna arms at the antenna throat, whereby a control electrode of each of the pair of transistorized amplifiers is arranged to be less than one quarter of a wavelength of the highest frequency in an energy spreading band occurring in the Vivaldi antenna system from the proximal ends of the antenna arms.

[0047] 9. The Vivaldi antenna system of Concept 8 wherein the pair of transistorized amplifiers are FET amplifiers, preferably formed from GaN FET devices, and wherein the control electrode is a gate of said FET amplifiers.

[0048] 10. The Vivaldi antenna system of Concept 8 or 9 wherein the pair of transistorized amplifiers are embodied as common-source FET amplifiers.

[0049] 11. A Vivaldi antenna system comprising: a Vivaldi type receiving antenna, the receiving antenna operating in a "traditional band" of operation (wherein the size of the Vivaldi type receiving antenna is >= 1 / 2 wavelength (λ) at the minimum frequency in the "traditional band" of operation) and a low frequency "extended band" (wherein the size of the Vivaldi type receiving antenna is <λ / 2); a buffer amplifier, the buffer amplifier having at least one pair of FET amplifiers, each of the pair of FET amplifiers having a gate electrode directly coupled to an arm of the Vivaldi type receiving antenna, each of the pair of FET amplifiers having an input impedance much higher than the characteristic impedance of the Vivaldi type receiving antenna in the extended band.

[0050] 12. The Vivaldi antenna system of Concept 11 wherein the FET amplifier is formed from a GaN device.

[0051] 13. The Vivaldi antenna system of Concept 11, wherein each gate electrode of the FET amplifier is arranged in close proximity to a respective one of the distal ends of an arm of a Vivaldi type receiving antenna.

Claims

1. A Vivaldi antenna system, comprising a Vivaldi antenna, the Vivaldi antenna being configured to impedance match an antenna impedance Za above a frequency fc; a field effect transistor FET buffer, the buffer being coupled to a terminal of the Vivaldi antenna, the coupling length between the antenna terminal and the buffer being less than a quarter of the highest wavelength of an extended frequency band, wherein: The extended frequency band is a frequency band less than a frequency fc, the buffer is configured to present an input impedance higher than the antenna impedance Za at frequencies less than the frequency fc, and the buffer output impedance is further configured to match the system impedance Z0 at frequencies both above and below fc, wherein: The Vivaldi antenna includes a pair of antenna arms that diverge from each other as they radiate from a proximal end at the antenna throat; The FET buffer includes a buffer amplifier having at least one pair of transistorized amplifiers, the buffer amplifier being embodied in an IC chip having chip contacts coupled to the proximal end of the antenna arm at the antenna throat by direct bonding; and The length of the coupling between the antenna terminal and the buffer is the length between the control electrode of the transistorized amplifier and the proximal end of the antenna arm.

2. The Vivaldi antenna system according to claim 1, wherein: The buffer includes a GaN FET.

3. The Vivaldi antenna system according to claim 1, wherein: The antenna has a balanced feed and the buffer has a balanced input.

4. The Vivaldi antenna system according to claim 3, wherein: The buffer has a differential output.

5. The Vivaldi antenna system according to claim 3, wherein: The buffer has a single-ended output.

6. The Vivaldi antenna system according to any one of claims 1 to 5, wherein: The Vivaldi antenna also includes a traditional frequency band operating above a frequency fc, wherein the traditional frequency band makes the size of the Vivaldi antenna greater than or equal to 1 / 2 wavelength (λ) at the minimum frequency of the traditional frequency band, and in the extended frequency band, the size of the Vivaldi antenna is less than 1 / 2 wavelength (λ) at the minimum frequency.

7. The Vivaldi antenna system according to claim 6, wherein: The buffer includes an RC high-pass feedback network.

8. The Vivaldi antenna system of claim 1, wherein each gate electrode of the transistorized amplifier is connected to a corresponding one of the proximal ends of the arms of the Vivaldi-type receiving antenna using a vertical metal via.

9. The Vivaldi antenna system of claim 1, wherein the length of the coupling between the antenna terminal and the buffer is less than one tenth of the wavelength of any frequency of the extended frequency band.

10. The Vivaldi antenna system of claim 1, wherein the pair of transistorized amplifiers are FET amplifiers.

11. The Vivaldi antenna system of claim 10, the pair of transistorized amplifiers being formed from GaN FET devices, and wherein the control electrode is a gate of the FET amplifiers.

12. The Vivaldi antenna system of claim 1 or 10, wherein the pair of transistorized amplifiers are embodied as common-source FET amplifiers.

13. The Vivaldi antenna system of claim 12, wherein each gate electrode of the transistorized amplifier is connected to a corresponding one of the proximal ends of the arms of the Vivaldi-type receiving antenna using a vertical metal via.

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