Fabry-Perot Antenna Research Articles

Bidirectional and Circularly Polarized Fabry–Perot Antenna Based on Self-Complementary Metasurface for Millimeter-Wave Applications

Bidirectional and Circularly Polarized Fabry–Perot Antenna Based on Self-Complementary Metasurface for Millimeter-Wave Applications

A Stable-Gain Millimeter-Wave Fabry-Perot Antenna Based on Circular Polarizer-Integrated PRS with Positive Reflective Phase Gradient

In this paper, we present a millimeter-wave Fabry-Perot antenna with dual resonances, circular polarization, and stable gain. To achieve circularly polarized radiation, we integrate a receiver-transmitter circular polarizer into the partially reflective surface (PRS) of the antenna. The PRS is specifically designed with a positive reflective phase gradient, which contributes to a stable gain in the dual-resonance frequency band. For the radiation source, we adopt a linearly-polarized substrate-integrated waveguide cavity-backed slot fed by a printed ridge gap waveguide. Experimental measurements conducted on a fabricated prototype of the proposed antenna demonstrate its impedance and axial ratio bandwidths of 28.6–30.0 GHz and 28.6–29.6 GHz, respectively. Furthermore, the antenna exhibits a peak gain of 12.1 dBi and a gain fluctuation lower than 0.6 dB within the operational frequency band.

An anisotropic PRS for squinting the radiation pattern with gain improvement of MIMO system

This work presents the design and analysis of a new anisotropic Partial Reflective Surface (PRS) to address beam squinting as well as gain improvement, using the phase gradient property of periodic structure in a 3-port Multiple Input Multiple Output (MIMO) system. An angular tilt of 30° is obtained relative to the boresight direction by manipulating the transmission properties. Additionally, the gain is improved by utilizing a homogenous PRS. Gradation constant is realized by changing the radius of adjacent unit cells in a dielectric host structure, ensuring a continuous variation in PRS properties. The formation of a Fabry-Perot antenna reduces the overlap between the adjacent beams, improving field correlation and isolation performance, in addition to gain enhancement. Furthermore, two 1 × 5 absorbers are strategically placed between the radiating elements to minimize the surface currents and achieve high port isolation. This combination of PRS and absorber leads to reduced field-to-field coupling and port-to-port coupling, thus achieving high signal isolation and beam squinting accuracy. The effectiveness of the proposed approach is validated through simulations, which are further supported by an equivalent circuit model. Experimental validation is also conducted to verify the results obtained.

Fabry–Perot Antenna Based on an Electrically Tunable Slot Antenna and a Two-Layer Frequency-Selective Surface

Introduction. One of the directions in Fabry–Perot antenna design consists in increasing its operation frequency range. In the present work, we set out to develop a Fabry–Perot antenna with a smooth gain pattern across a wide frequency range. To that end, a tunable slot antenna based on a thin-film ferroelectric varactor was used. The major development criterion was a high uniformity of the gain pattern, not exceeding 1 dB in the given frequency band. Aim. To develop a Fabry–Perot antenna for the 4.9–5.5 GHz frequency range with a high gain uniformity within the operating frequency band.Materials and methods. The antenna under development was based on thin-film ferroelectric capacitors as tunable elements. Fluoroplastic plates metallized on both sides were used as a dielectric material for manufacturing a frequency selected surface and a slot antenna. The parameters of ferroelectric elements were measured using a resonance technique, while the parameters of the dielectric material were determined using the Nicholson–Ross–Weir method.Results. The developed antenna has an operating frequency band of 4.9–5.5 GHz. Samples of ferroelectric capacitors and foiled dielectric material were manufactured and experimentally investigated. A tunable slot antenna was fabricated, and its characteristics were measured. The simulation results show that the gain value of the developed Fabry–Perot antenna is not less than 10 dB in the operation frequency range. Variations in the gain value within the operating frequency band do not exceed 0.7 dB.Conclusion. A Fabry–Perot antenna based on an electrically tunable slot antenna and a two-layer frequency-selective surface was developed. The operating frequency band of the developed device ranges within 4.9–5.5 GHz, which corresponds to the frequency band of Wi-Fi networks. Optimization of the antenna design parameters made it possible to achieve higher gain values under their minor variations in the operation frequency band.

Broadband dual-polarized antenna array with enhanced radiation pattern stability

ABSTRACTIn this paper, a broadband dual-polarized antenna array with stable radiation pattern is proposed for 5 G base station applications. The proposed antenna array consists of a 2 × 2planarantennaarray, four 2 × 2 circle patch parasitic structures and a metal reflector. Based on the principal of the FP (Fabry-Perot) antenna to achieve the stable radiation pattern, when the parasitic loading height meets the resonant height of the FP antenna, serious radiation pattern distortion in large reflector environment could be improved effectively. A prototype of the 2 × 2 broadband dual-polarized antenna array is designed and fabricated. The measured results show that the −10 dB bandwidth of the proposed broadband dual-polarized array is able to cover 3.23–5.06 GHz with high isolation which is greater than 25 dB over the entire operating band. The antenna elementsofthearrayarecapableofmaintainingstable radiation pattern throughout the operating frequency range. The HPBW (half-power beam-width) in the horizontal plane is effectively controlled at 67°±5°with a gain of 8.8 ± 0.5 dBi. Due to the stable radiation performance mentioned above, the proposed dual-polarized array can be applied to future 5 G and sub-6 G base station applications.

Dual Circularly Polarized Fabry–Perot Antenna Using Single-Layer Self-Polarizing PRS

Dual Circularly Polarized Fabry–Perot Antenna Using Single-Layer Self-Polarizing PRS

Reconfigurable integrated structures with functions of Fabry–Perot antenna and wideband liquid absorber for radar system stealth

This paper proposes a functionally reconfigurable integrated structure of a Fabry–Perot (FP) antenna and wideband liquid absorber. First, a two-layer partial reflecting surface (PRS) has been designed. Then, a patch antenna is used to act as the source antenna. By combining the source antenna with the PRS, an FP antenna has been designed. What’s more, taking full advantage of the reflective properties of PRS, a liquid broadband absorber is then designed. Last, the integrated structure with two functions has been realized. It can be used as the FP antenna or the liquid absorber through the extraction and injection of ethanol. In this way, it is effective to switch between stealth and detection states which can be used in different electromagnetic environments. The PRS is elaborately tailored to serve as both a component of the FP antenna and the metal ground of the broadband liquid absorber. Then the integrated structure is realized by combining the FP antenna with the liquid absorber. The PRS is composed of patches on the top layer of the substrate and the square loop on the bottom. The liquid absorber is composed of a 3-D printed container, 45% ethanol layer and the PRS is used to serve as the metal ground. The formula of Mie resonance theory has been extended and used to design the liquid absorber. The gain of the antenna is 19.7 dBi when the ethanol is extracted. When the ethanol is injected, a wideband liquid absorber is achieved. The absorption band (S11 < − 10 dB) ranges from 4 to 18 GHz. The absorption bandwidth is over 133%. The monostatic RCS reduction bands of the structure with ethanol range from 4 to 18 GHz and the average RCS reduction is 28.4 dBsm. The measured and simulated results are in good agreement.

Gain and Frequency-Selectivity Enhancement of Dual- Polarized Filtering IBFD Antenna Using PRS

A dual-polarized filtering Fabry–Perot antenna (FPA) with high selectivity and high isolation is proposed for in-band full-duplex (IBFD) applications. The proposed antenna utilizes a square patch as the feeding element, which is fed by a double differential-fed scheme for dual-polarized radiation with high isolation. The patch is loaded with a symmetrical cross-slot and four shorting pins for a broad passband filtering feature. To enhance broadside gain across a wide frequency range, the patch is incorporated with a partially reflecting surface (PRS), which is composed of two complementary cross-slot and patch arrays. Moreover, the frequency selectivity of PRS is exploited to improve the filtering characteristic. The double differential feeds are realized based on out-of-phase power dividers, which are combined with simple low-pass filters to further improve the out-of-band suppression. The final design was fabricated and measured. The measurement results show excellent results with a 10-dB return loss bandwidth of 21.5% (4.91–6.09 GHz), isolation of greater than 40 dB, peak gain of 13.7 dBi, out-of-band suppression level of better than 27 dB, and a cross-polarization level of less than –27 dB.

A Fabry–Perot antenna using a frequency selective surface layer with wideband and Low RCS for Mm-wave applications

In this article, a Fabry-Pérot cavity antenna operating in the K-band is introduced, offering wideband, high gain with low RCS properties. The design consists of a patch antenna serving as a feed antenna and a bianisotropic frequency selective surface (FSS) layer incorporated to create a Fabry–Perot antenna for expanding the bandwidth, intensifying the gain, and minimizing radar cross-section (RCS). The proposed Fabry–Perot antenna is fabricated and measured, showing good agreement between simulated and measured results. The results show an impedance bandwidth of 23.6 % and a 3-dB gain of 14.1% at the center frequency of 28 GHz.

Methodology and Implementation of Beam Steering Using C-Shaped Split Rings for Fabry–Perot Antennas

The design process of beam-steering partially reflective surface (PRS) made up of C-shaped split-ring resonators (CSRRs) is presented in this article. Through analyzing the transmission characteristics of CSRRs with variable opening angles and orientations, spatially abrupt phase and magnitude are introduced over PRS to reshape the wavefronts of linear polarization waves. Based on the designed two distributions and the two control methods, four arrangements of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\times $ </tex-math></inline-formula> 5 CSRRs are fabricated to validate the design methodology of beam steering. Furthermore, two reconfigurable Fabry–Perot (FP) antennas are proposed based on liquid-metal and mechanically rotating reconfiguration. An agreement between simulated and measured results shows higher aperture efficiency and desirable radiation patterns while demonstrating excellent reconfiguration reliability. Besides, an eight-element phased array combined with liquid-metal PRS is fabricated and shows improved scanning performance and stable gain fluctuation.

A High-Gain Filtering Fabry-Perot Antenna With RCS Reduction

A High-Gain Filtering Fabry-Perot Antenna With RCS Reduction

A Fabry–Perot Conical Beam Antenna With Multi-Polarization Reconfigurable Capability

In this communication, a Fabry–Perot (FP) conical beam antenna with multipolarization reconfigurable capability is proposed. A single-layer partially reflective surface (PRS) with circular slots is designed for the prescribed flare angle determined by the height of the FP antenna and resonant frequency. A group of Vivaldi patches with a set of shorting vias around a common central axis on a printed circuit board (PCB) are used as the primary source, which is fed by nested coaxial waveguide. Vivaldi patches coupled with parallel baluns, which are connected to the internal coaxial waveguide, are used to produce a horizontally polarized conical beam. A vertically polarized conical beam can be obtained when the external coaxial waveguide is used to feed the Vivaldi patches. When circularly polarized conical beams are required, the internal and external coaxial waveguides need to be excited at the same time with the same amplitude and the proper phase difference. A prototype of the proposed FP conical beam antenna with multipolarization reconfigurable capability at 12 GHz is designed, fabricated, and measured to verify the concept. The measured results are in good agreement with the simulated ones. A maximum gain of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\ge 12.8$ </tex-math></inline-formula> dBic is achieved with the proposed FP conical beam antenna for the two circular polarization states, with an axial ratio (AR) and impedance bandwidth (IBW) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\ge 16.7$ </tex-math></inline-formula> % and 8%, respectively. The maximum gain and IBW for the horizontal polarization (HP) and vertical polarization (VP) are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&gt;13.2$ </tex-math></inline-formula> dBi and 9.2%, respectively.

Broadband Dual-Polarized Fabry–Perot Antenna With Simple Feed for Full-Duplex Applications

In this letter, we present a simple-feed dual-polarized Fabry–Perot antenna with broadband and high-isolation for in-band full-duplex applications. Its feeding element consists of a two-port patch antenna with one aperture coupled port and one microstrip-line-fed port for a high isolation without adding any out-of-phase power divider. For broadband and high-gain radiation, the two-port patch is incorporated with a stacked-patch and partially reflecting surface while maintaining the structure symmetry. The final design with an overall size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim\! 1.9\lambda _{\text{min}}$</tex-math></inline-formula> × 1.9 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{\text{min}}$</tex-math></inline-formula> × 0.48 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{\text{min}}$</tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{\text{min}}$</tex-math></inline-formula> is the free-space wavelength at the lowest operational frequency) has been fabricated and tested. The measurements result in a 10 dB return loss bandwidth of 19.1% (4.84–5.86 GHz), an isolation of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\ge$</tex-math></inline-formula> 43 dB, a realized broadside gain of 12.4–14.2 dBi, cross-polarization level of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\le$</tex-math></inline-formula> −30 dB, and side-lobe level of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\le$</tex-math></inline-formula> −18 dB across 5.00–5.95 GHz.

A dual‐polarized wideband gain enhancement Fabry–Perot antenna by adopting a wedge‐shaped phase correcting structure

A dual-polarized wideband Fabry-Perot (FP) antenna based on a wedge-shaped phase correcting structure (WPCS) is proposed. The antenna adopts a wideband dual-linear polarized slot-coupled antenna as a primary antenna, and adopts a single-layer FSS structure with positive reflection phase gradient characteristics as a partially reflecting surface (PRS) of the FP resonator, to optimally excite the FP cavity resonances within a wide operating band. Moreover, a small circular metal patch array is printed on the other side of the FSS unit structure. The small circular patch array effectively increases the reflection amplitude without changing the positive reflection phase gradient characteristics of the PRS, which improves the FP antenna gain. In addition, a highly graded WPCS is loaded in the resonant cavity to properly compensate the phase between different reflection paths inside the resonant cavity, which enhances the gain of the FP antenna in a wide band. Finally, the measured peak gains of the FP antenna under the excitation of Port 1 and Port 2 are 16.0 dBi and 15.89 dBi, respectively, and the gain enhancement can reach up to 3 dBi after loading the WPCS. The measured 10-dB impedance-matching operating bandwidth of dual-polarized common coverage is 14.08 to 16.45 GHz (15.53%).

Analysis and Design of Wideband Low-RCS Fabry–Perot Antennas With Reduced Profile

In this article, two incomplete partially reflective surface (PRS)-based Fabry–Perot (F-P) antennas each with a high gain, wideband low radar cross section (RCS), and reduced profile are proposed. The reductions of the antenna profiles and RCS are realized based on artificial magnetic conductor (AMC) surfaces and the phase cancellation, respectively. In the first design, two AMC surfaces are placed around the radiation patch and above the PRS. The thickness of the F-P cavity is reduced by half due to the zero-phase reflection of the lower AMC surface around the radiation patch. The income waves are partly reflected by the upper AMC surface above the PRS with zero reflection phase and partly penetrate the PRS and then reflected by the lower AMC surface also with zero reflection phase. The reflected EM waves from the bottom AMC surface travel another distance of quarter wavelength in the upward direction making the total electrical path traveled be half wavelength, thereby causing a phase shift of 180° with the reflected waves from the upper AMC surface, and thus resulting in a wideband RCS reduction. For the second design, another AMC surface is placed below the PRS. On one hand, the middle and lower AMC surfaces have the same reflection phases and then an F-P cavity with a subwavelength thickness is generated. On the other hand, the phase difference between the upper and lower AMC surfaces is also designed as 180°, which is used to suppress the total backward RCS. The two F-P antennas are both fabricated and measured. Measured results validate their reflection, radiation, and scattering performance well. To the best of our knowledge, this work is the first design, which integrates the physical (thin F-P cavity), radiation (gain enhancement), and scattering (broadband RCS reduction) performance of the F-P antenna.

Dual circularly polarized Fabry-Perot antenna with metamaterial-based corner reflector for high gain and high aperture efficiency

Based on the ray-tracing model, a new method of achieving a high gain and high aperture efficiency Fabry-Perot antenna with metamaterial-based corner reflector is proposed. The proposed Fabry-Perot antenna is composed of a dual circularly polarized patch antenna feed and the metamaterial-based corner reflector. The metamaterial-based corner reflector consists of four phase correction metasurfaces and a partially reflective surface. First, theory and analysis of the Fabry-Perot antenna with metamaterial-based corner reflector are presented. Then, the performances of the dual circularly polarized antenna feed, the traditional Fabry-Perot antenna, and the Fabry-Perot antenna with metamaterial-based corner reflector are compared among each other and analyzed. Finally, the proposed Fabry-Perot antenna is fabricated and measured. The measured left-hand circular polarization (LHCP) gain and the measured right-hand circular polarization (RHCP) gain of the proposed Fabry-Perot antenna are 21.4 dBi and 21.3 dBi, respectively. Comparing with the antenna feed, the LHCP gain and RHCP gain of the proposed Fabry-Perot antenna are enhanced by 16.4 dB and 16.3 dB, respectively. Compared with the traditional Fabry-Perot antenna, the metamaterial-based corner reflector acts as both a reflection surface and a phase correction surface. It manipulates the propagation direction and phase of electromagnetic wave. The proposed Fabry-Perot antenna with high gain, high aperture efficiency and low sidelobe at 2.8 GHz paves the way for developing the solar radio telescope and conducting the observation.

Spectral Analysis of Broadband Fabry–Perot Antennas With Multiple Coupled Cavities

The anomalous dispersion observed in wideband Fabry–Perot Antennas formed by multiple coupled cavities is explained in terms of modal coupling between several leaky waves. In this way, the negative group velocity associated to the homogenized mode can be explained. Moreover, the enhancement in the radiation pattern bandwidth can also be described from the contribution of these coupled leaky waves to the total interference pattern. Theoretical dispersion results are reported for 1-D and 2-D Fabry–Perot Antennas with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N =$ </tex-math></inline-formula> 2 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N =$ </tex-math></inline-formula> 3 coupled cavities operating in broadside and off-broadside scanned patterns. The theory is also corroborated with experimental results.

Differential-Fed Dual-Polarized Filtering Fabry-Perot Antenna With High Isolation

In this paper, a dual-polarized filtering Fabry-Perot antenna (FPA) with high-isolation is proposed. It consists of a feed element of differential-fed dual-polarized square patch and a partially reflecting surface (PRS). The patch is capacitively coupled with T-shaped resonators and shorting-vias to obtain broadband characteristic and radiation nulls. The PRS structure is composed of two complementary metasurface layers are selected for achieving a positive reflection phase gradient within the broad frequency range. More interestingly, thanks to the frequency selectivity feature, the PRS significantly enhances the filtering characteristic of the FPA. For verification, a prototype of the proposed antenna operating at the 5.5-GHz center frequency has been fabricated and measured. The prototype with an overall size of ~2.0λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> × 2.0λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> × 0.49λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> is the free-space wavelength referring to the lowest operational frequency) result in an impedance bandwidth of 17.1% (5.02 – 5.96 GHz) for 10-dB return loss and a high isolation of ≥ 45 dB. Moreover, the far-field measurements result in a good dual-polarized radiation with the peak gain of 13.0 dBi, cross-polarization level of ≤ –25 dB within the passband, and out-of-band suppression level of ≥ 20 dB.

Investigations and prospects of Fabry-Perot antennas: A review

Fabry-Perot (FP) antennas have characteristics of planar structures combined with high gain, and they have been widely used in wireless communications. With the progress of ongoing research, FP antennas have achieved various capabilities, but many of them are still under development, such as low-profile, wideband, circular polarization, multi-band, low-radar cross section (RCS) and reconfigurable features. This paper discusses the theoretical analysis methods and research progress of FP antennas, and explains the realization methods of different features of FP antennas. In order to indicate different technologies for realizing various capabilities, the key technologies and features of some of the latest designs are described. Finally, the research situation and prospects of FP antennas are summarized to guide their research directions in the future.

Broadband RCS reduction for both microstrip array and Fabry‐Perot antenna based on the quasi‐ AMC superstrate

This article presents a new type of quasi-AMC superstrate (QAMCS), which can achieve wideband RCS reduction (RCSR) for both the microstrip array and Fabry-Perot (FP) antenna. The proposed QAMCS comprises of two-layer metallic patterns with a thin air gap. The top-layer consists of two types of frequency selective surfaces (FSSs) in a checkerboard layout, and the wideband RCSR is realized based on the phase cancelation principle. The bottom-layer consists of the slotted FSS, to reflect out-of-band signal while allowing the in-band signal to pass through with a low insertion loss. Besides, the reflection phase of the proposed QAMCS is about −180° around higher frequencies. Therefore, it can be regarded as a partially reflecting surface (PRS) to construct the FP antenna with a highgain and low-RCS. The simulation and measurement results show that the bandwidth of 10-dB RCSR is more than 76% (7.2-16.1 GHz). The 10-dB impedance bandwidth of the array antenna is ranging from 16.6 to 18.6 GHz. For the FP antenna, its aperture efficiency is 31.5% and the peak gain is 17.5 dBi at 20 GHz.