Patch Subarrays Research Articles

Design of a High-Order 2 × 2 SIW Cavity-Backed Patch Subarray and Its Application in Millimeter-Wave CP Filtenna Array

A novel millimeter-wave 2 × 2 substrate integrated waveguide (SIW) cavity-backed patch subarray with a simplified feeding structure is presented. Two higher order SIW cavity modes (quasi-TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">410</sub> and quasi-TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">330</sub> modes) are designed using eigenmode analysis to support 2 × 2 patches with in-phase radiation. The proposed 2 × 2 patch subarray has multiple resonant modes and a simplified feeding network. Moreover, this subarray can create a radiation null at the upper band edge, which helps to synthesize the filtering response. To verify the potential application in large-scale array, four 2 × 2 subarrays are combined into a 4 × 4 circularly polarized filtenna array with a filtering sequentially rotated feeding network. The measurements of the fabricated filtenna array show an operating bandwidth of 8.9% from 26.6 to 29.1 GHz (| <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | < −10 dB and AR < 3 dB), a peak gain of 15.9 dBic, and stable boresight radiation patterns. Excellent bandpass filtering response with high out-of-band rejection levels of 32 and 48 dB in the lower and upper stopbands, respectively, is observed.

79 GHz Multilayer Series-Fed Patch Antenna Array With Stacked Micro-Via Loading

A wideband compact series-fed patch subarray is proposed for 79 GHz multiple-input—multiple-output (MIMO) radar. The proposed subarray is, for the first time, loaded with stacked micro-vias (SMVs). Two sets of patches in the subarray are fed 180° out-of-phase. A low-cost, high-resolution multilayer printed circuit board (PCB) technology, called “any-layer PCB,” is used to implement the SMVs, which cannot be done by standard high-definition interconnect PCB technology. Moreover, the technology supports small SMVs on different layers; hence, thick machine-drilled vias can be avoided. For comparison, a series-fed patch subarray with no SMV loading is designed. It is shown that SMV loading facilitates a larger overlap of the impedance and gain bandwidths, leading to a larger operating bandwidth. The measured 10 dB impedance and 3 dB gain bandwidths are 15% and 9.6%, respectively. The sidelobe suppression is above 12.9 dB, and the maximum array gain is 12.67 dBi at 79.1 GHz. This subarray is suitable for MIMO radar, as its width is around half-wavelength and the SMVs around it mitigate the crosstalk between the transmitting and receiving arrays.

Dual‐linear‐polarization substrate integrated waveguide patch antenna array

This article presents a 37 GHz compact patch antenna array which can generate dual-linear-polarization (LP) from a single radiating aperture for mm-wave applications. The antenna adopts dual-layer structure to achieve miniaturization and also to design the feeding network. The substrate integrated waveguide (SIW) feeding network is built in the bottom layer. On the top layer, multi-strip ±45° polarized series-fed patch subarrays are fabricated. Patches with variable width and two eight-way unequal power dividers are employed to suppress the sidelobe level (SLL) in two planes. A 90° 3 dB coupler with a 90° electric length of SIW is adopted to realize same phase and opposite phase. Thus, two polarized waves, namely vertical linear polarized wave (VLP) and horizontal linear polarized wave (HLP) can be generated. Finally, a prototype SIW patch antenna array is fabricated. The antenna gain is about 24–25 dBi for both VLP and HLP and SLL is under –12 dB in the frequency range of 36.5–37.5 GHz.

Expansion of the Beamforming Coverage Area in an Elevation Plane for 60 GHz Band 3-D Beamforming

This letter proposes a novel antenna structure for 60 GHz band 3-D coverage beamforming. By using the proposed antenna structure, the coverage area can be expanded in an elevation plane. Dipole and patch subarray antennas were packaged into one structure by using the copper balls interconnection technique. A simple idea to utilize dipole and patch elements enables endfire and broadside radiations resulting in the coverage area expansion in the elevation plane. Two 2 × 4 array antennas were made up of eight multilayered substrate. Six metal layers were used for each multilayered substrate.

A Low-Profile Beamforming Patch Array With a Cosecant Fourth Power Pattern for Millimeter-Wave Synthetic Aperture Radar Applications

In this article, a novel beamforming patch array with a cosecant fourth power pattern is proposed for millimeter-wave synthetic aperture radar (SAR) applications. It enables radar receiving identical power in the field of view, provided that the radar cross section levels of targets within the illuminated area are similar. Different from “one-way” communication application, the SAR is a “two-way” system such that the received power is inversely proportional to $R^{4}$ , not $R^{2}$ , where $R$ is the distance between target and radar. Thus, conventional cosecant squared patterns are not suitable for SAR. Here, the concept and link properties of the proposed cosecant fourth power pattern are introduced, while its synthesis process is facilitated by a mixed optimization method, including nonlinear fitting and active pattern methods. As demonstrated, an array prototype, which consists of 12 series-fed patch subarrays and a substrate integrated waveguide network for power distributing and phase shifting, is designed and fabricated. Particularly, the power-distributing section only consists of symmetrical T-junctions with equal power division, thus making the antenna more tolerant to fabrication error. Good cosecant fourth pattern performance is achieved from 23.8 to 25.0 GHz. The presented array also owns the advantage of low profile ( $\sim 0.09\lambda _{0}$ ), compact, reliable, and low cost.

A compact feeding network with radiation contribution for X‐band marine radar antenna array applications

AbstractA compact feeding network with radiation contribution is proposed in designing microstrip patch array antenna (MPAA) for X‐band marine radar applications. The 1‐to‐4 feeding network consists of two circular‐sector patch balun, which can radiate electromagnetic wave with the same polarization of the patch array for enhancing the gain and suppressing the cross polarization. The feeding line in the series‐fed patch subarray is modified as the step‐impedance microstrip line to decrease the side‐lobe level (SLL). To verify the method, a 28‐element 9.41‐GHz MPAA with the proposed radiated feeding network is designed and fabricated. Measured results show that the impedance bandwidth is 183 MHz with a peak gain of 21.3 dBi. The SLL is 27.8 and 21.4 dB in the E‐ and H‐planes, respectively. The cross polarization is effectively reduced, which is lower than the copolarization of about 57 dB.

A Metasurface-Based Multilayer Wideband Circularly Polarized Patch Antenna Array With a Parallel Feeding Network for Q-Band

In this letter, a metasurface (MS)-based multilayer wideband circularly polarized (CP) 4 × 4 truncated corner patch antenna array is proposed for Q-band applications. The patch array consists of four 2 × 2 patch subarrays, an MS structure, and an H-shaped substrate integrated waveguide power divider. Each 2 × 2 patch subarray acts as the CP radiating element, which is fed by a compact parallel-fed microstrip power divider using a sequential rotation technology. The MS structure has 4 × 4 square plates covering over each patch to improve | S 11|, axial ratio (AR), and gain performances. The antenna was fabricated and measured to verify the practical feasibility. −10 dB | S 11| bandwidth of 32% (37.4–52.2 GHz), 3 dB AR bandwidth of 25.8% (39.2–51.5 GHz), 3 dB gain bandwidth of 27.6%, and the peak gain of 18.2 dBic are achieved in the vicinity of 45 GHz.

A Q-Band Low-Profile Dual Circularly Polarized Array Antenna Incorporating Linearly Polarized Substrate Integrated Waveguide-Fed Patch Subarrays

An integrated low-profile dual circularly polarized (dual CP) array antenna operating in the Q-band is proposed in this paper, which is realized by sequentially rotating subarrays comprised linearly polarized (LP) substrate integrated waveguide (SIW)-fed patches. The design methodology and working mechanism of the LP SIW-fed patches is presented first, which is implemented with a two-layer printed circuit board structure where the SIW feeding network is located in the bottom substrate and the patches are on the top substrate. Four subarrays are then arranged according to the requirements of a sequential rotation array for producing CP directive beams. A two-layer SIW feeding network for providing the required amplitude and phase distributions for the four subarrays is designed, which includes two input ports for exciting CP radiation with opposite handedness, respectively. Prototypes of the LP subarray and the integrated dual CP array antenna were fabricated and measured. Good agreement between the simulation and measured results validates the designs. The proposed low-cost and lightweight dual CP antenna owns the advantages of wide useful bandwidth (8.9%), high isolation of more than 19 dB, low profile of less than $0.1\lambda _{0}$ , and good orthogonal polarization discrimination higher than 25 dB.

Enhancing Communications for Future Mars Rovers: Using high-performance circularly polarized patch subarrays for a dual-band direct-to-Earth link

The recent success of the Mars Science Laboratory (MSL) has garnered worldwide interest in further exploration of Mars. In this article, we discuss our latest developments in circularly polarized (CP) patch subarrays to be integrated into a larger 30-dB gain array. This larger array will facilitate an enhanced dual-band direct-to-Earth (DTE) link with NASA's Deep Space Network at the X band. The frequency ratio between both bands is rather small, with a value of 1.17, and current dual-band or wide-band CP patch elements are not easily suited for X-band frequencies, antenna array requirements, or the harsh environments in space.

Low-Profile Broadband Dual-Polarized Integrated Patch Subarray for X-Band Synthetic Aperture Radar Payload on Small Satellite

A low-profile broadband dual-polarized patch subarray is designed in this letter for a highly integrated X-band synthetic aperture radar payload on a small satellite. The proposed subarray is lightweight and has a low profile due to its tile structure realized by a multilayer printed circuit board process. The measured results confirm that the subarray yields 14-dB bandwidths from 9.15 to 10.3 GHz for H-pol and from 9.35 to 10.2 GHz for V-pol. The isolation remains better than 40 dB. The average realized gains are approximately 13 dBi for both polarizations. The sidelobe levels are 25 dB for H-pol and 20 dB for V-pol. The relative cross-polarization levels are 30 dB within the half-power beamwidth range.

A Low Profile, Ultra-Lightweight, High Efficient Circularly-Polarized Antenna Array for Ku Band Satellite Applications

A novel low-profile, ultra-lightweight, high-efficient circularly polarized (CP) planar patch antenna array is reported for Ku-band satellite TV reception applications. The basic radiating element of the antenna array is realized by a $2 \times 2$ corner-removed patch subarray. This $2 \times 2$ patch subarray is center-fed by a rectangular coupling aperture etched on the top surface of a substrate-integrated-waveguide cavity. A novel compact sequential rotation feeding technique is adopted to broaden the operating bandwidth without occupying additional area. The $2 \times 2$ CP subarray can be easily scaled up for large size antenna arrays due to its single layer feeding network and compact radiating elements. In addition, the patch radiators are printed on a thin layer of Polyimide film backed by a piece of supporting foam to minimize the entire weight. To verify the design concept, a 96-element ( $16 \times 6$ ) CP patch array was fabricated and tested. Measured results show that the operating bandwidth is 700 MHz from 11.55 to 12.25 GHz. The gain is stable across the operating bandwidth with a realized peak gain of 26.4 dBic. The height of the antenna is $0.05~\lambda _{0}$ and the total weight is only 66.5 g. It serves as an excellent candidate for Ku-band satellite applications.

Analytic study on CP enhancement of millimeter wave DR and patch subarray antennas

This article presents a comparative analysis for the performance of single, 2 × 2, and 4 × 4 dielectric resonator (DR) and patch circularly polarized (CP) antenna subarrays at 30 GHz. In order to enhance the CP bandwidth, the subarray elements are fed by two kinds of sequential feeding techniques using parallel and hybrid ring feeds. The 4 × 4 patch antenna subarrays fed by parallel and hybrid ring feeding networks are fabricated and tested. Measurements show acceptable agreement with simulation results. The experimental results show a bandwidth of 36.9% for both (−10 dB) impedance matching and (3 dB) axial ratio CP patterns for the patch subarray antenna with hybrid ring feeding. For the parallel feeding, the corresponding bandwidth is 28.81%. The proposed antennas combine desirable features such as wide impedance and AR bandwidths, low profile, and easiness of fabrication and therefore is a good candidate for millimeter wave systems around 30 GHz.

Ka-band phased patch array antenna integrated with a PET-controlled phase shifter

In this article, a 4 × 4 linear-phased patch array antenna, consisting of four 1 × 4 patch subarrays and a true time-delay multiline phase shifter, is proposed on a thin film liquid crystal polymer substrate at Ka-band. The patch antenna is designed with a gain of 6 dBi at 35 GHz and a bandwidth of 23% centered at 35 GHz. To enhance the gain and symmetrize the beam patterns of the 4 × 4 array, a 1 × 4 patch subarray in the E-plane was designed and characterized. The subarray produces an enhanced gain of 11 dBi and a wide beamwidth of ±38° in the H-plane for beam steering. The proposed phase shifter comprises a 1 × 4 microstrip line power splitter and a piezoelectric transducer-controlled phase perturber. A large phase variation of up to 370° and a low insertion loss of less than 2 dB were demonstrated for the phase shifter at Ka-band. The integrated phased array attains a gain of 15.6 dBi, and a continuous true-time delay beam steering of up to 33 ± 1° from 31 to 39 GHz. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2015.

Novel Parasitic Micro Strip Arrays for Low-Cost Active Phased Array Applications

In this paper, a novel idea is proposed to construct low-cost phased arrays by using the multi-port property of array elements. The operating principles are illustrated and explained in detail. A three-element patch subarray with a periodic lattice is conceived according to the proposed idea. In the subarray, one patch antenna with multiple ports is designed as an active element which is directly fed through the excitation port by a feeding network. The other two parasitic patches are fed by the coupling ports of the active element. Good agreements between simulations and measurements of a two-subarray phased array prototype successfully verify the proposed idea. Then, comparisons to a conventional phased array are performed to highlight its advantages, e.g., high aperture efficiency and low cost. Finally, a second design example is given for more references.

Substrate-Integrated Cavity-Backed Patch Arrays: A Low-Cost Approach for Bandwidth Enhancement

The substrate-integrated waveguide (SIW) technology is utilized as an alternative low-cost approach in fabricating cavity-backed patch antennas. The proposed antenna arrays combine the attractive features of the conventional metalized cavity-backed patch arrays like surface wave suppression, high radiation efficiency, and enhanced bandwidth, yet provide a low manufacturing cost. A previously developed design of a 2×2 SIW cavity-backed microstrip patch sub-array is extended here and used as a basic building block to attain larger arrays of 2 × 4, 4 × 4, and 8 × 8 elements. The fabricated arrays have been measured and demonstrate good agreement with their simulated performance. The design and performance of these arrays are compared to other conventional bandwidth enhancement techniques, which prove SIW as a viable alternative.