Parasitic Patch Research Articles

Low-profile dual-polarized differential-fed filtering antenna and its novel array with low sidelobe level

This paper presents a single-layer dual-polarized filtering antenna with good out-of-band suppression. By using inherent characteristic of the patch’s eigenmode and meanwhile merging four filtering strategies, i.e., parasitic patches, slot on the driving patch, and defected groundstructure (DGS), a low-profile filtering antenna design with five radiation nulls has been realized. With the designed filtering antenna, a conventional 1×2 array with a spacing of 0.91λ is first developed. In order to reduce the sidelobe level of the array, a sharing patching scheme is introduced to decrease the interspace between the elements as 0.44λ, with the same physical size as the conventional array. In addition, a concept to measure total isolation between two kinds of the polarized ports in the array, i.e., SddVH, has been derived for the first time. The prototype of the proposed array is fabricated with a profile of 0.038λ. Measured results indicate that the designed novel array has an operational band of 3.53–4.06 GHz, SddVH better than 41 dB, a sidelobe level below −18 dB, and a suppression level above 20 dB with the stopband up to 0.5 GHz and 5 GHz.

Design of folded rectangular microstrip antenna on thinner substrate for wideband response

ABSTRACT Wideband microstrip antenna is realized by adding more than one resonant modes in the patch. In this paper, on electrically thinner substrate, design of modified shape rectangular microstrip antenna by employing folded rectangular patch is presented for linear polarized wideband response. Unlike the conventional rectangular patch, radiation pattern and resonance frequency at the second-order resonant mode are modified and along with the fundamental mode, yield wider bandwidth. On substrate of thickness 0.045λ0, folded patch design yields bandwidth of more than 20% along with the broadside radiation pattern and gain more than 8 dBi. Against the reported wideband designs, proposed design does not employ parasitic patches, resonant slot, modified ground plane structures, but on thinner substrate achieves the bandwidth of more than 20%. Resonant length formulation and subsequent design methodology are presented, which is useful in realizing similar folded antenna as per the specific frequency band. Simulated results have been experimentally verified, which shows close agreement.

On The Resonant Frequency and Bandwidth of Multilayered Square Patch Microstrip Antennas

In the present paper a novel technique has been developed to compute the resonant frequency and bandwidth of electromagnetically coupled multilayered square patch microstrip antenna (MLSPMA) on low (ɛr=2.33) and high (ɛr=10.8 ) index RT Duroid substrate in S and X band of microwave frequencies. The basic antenna structure considered is a multidielectric layered with a spaced parasitic director. The radiator (lower patch) and the parasitic patch (upper patch) are considered to have same and slightly different dimensions, and are perfectly registered (no offset). It is observed that the antenna geometry can be optimised for the required frequency operation and bandwidth by adjusting input parameters and the thickness of the layers.

A Ku/K‐band wideband crossed dipole circularly polarized array with low profile

AbstractA low‐profile Ku/K band circularly polarized phased array antenna based on crossed dipole and four parasitic elements is presented. Four parasitic patches and the outline of dipole arms which are designed as an exponentially gradual curve are intended to broaden impedance bandwidth. For better integrated design, the plated through holes at the bottom of substrate replaces the metal cavity, aiming to enhance the radiation characteristics of the positive direction. The small angle sequential ro0tation tech is adopted to further increase the axial ratio (AR) bandwidth. The 8 × 8 antenna array is operated from 15.5 to 23.5 GHz (41%), with the size of 56 mm × 56 mm × 2.54 mm. In the operating frequency, the array demonstrates an average peak realized gain of 24.3 dBic and has a 3‐dB AR beamwidth with scanning angle from −60° to 60° in the plane of ɸ = 0° and ɸ = 90°.

Dual-band filtering antenna with independent predetermined frequencies and low cross-polarization levels

In this paper, a dual-band filtering antenna with independent predetermined frequencies and low cross-polarization levels is proposed. In order to realize the independent control of frequencies of two radiation passbands, multiple additional structures such as rectangular slots, rectangular parasitic patches, and U-shaped slots are integrated on the traditional rectangular patch antenna to introduce new resonant modes and radiation nulls to the antenna, simultaneously. Since the generation structures of each frequency point are different, they do not affect each other. Besides, to obtain low cross-polarization levels, each additional structure is carefully adjusted such that the current vectors of each resonant frequency along the cross-polarized direction are quite weak. The proposed antenna operates in the 5G sub-6G (4050–4294 MHz) and the Wi-Fi 5.8 GHz band (5700–5920 MHz), and achieves cross-polarization levels of −37.8 and −36.8 dB in the lower and higher frequency bands, respectively. Compared to other multi-band filtering antennas, the proposed one has the advantages of independent predetermined frequencies and lower cross-polarization levels.

Wide E-Plane Beamwidth Microstrip Patch Antenna Using H-Shaped Gap-Coupling with Three Parasitic Patches for the K-Band

This article presents a new wide E-plane beamwidth rectangular microstrip patch antenna adopting H-shaped gap-coupling with three parasitic patches for the K-band vehicle parking monitoring system, while keeping single substrate. Both side and upper parasitic elements serve as λ and λ/2 resonators and are excited primarily by magnetic and electric couplings, respectively. The synthesis of radiation patterns from main and auxiliary elements results in the E-plane wide-beamwidth property. The proposed gap-coupling antenna provided the peak gain of 4.82 dBi, E-plane half-power beamwidth (HPBW) of 143.4°, and co-to-cross-pol ratios of 22.7 and 20.2 dB within the HPBW for the E- and H-planes, respectively. The presented geometry showed excellent figure of merits compared with others for the K-band.

Cost-Effective Broadband and Compact Patch Antenna Based on Ball Grid Array Packaging for 5G NR FR2 Band Applications

This brief introduces a compact, cost-effective broadband patch antenna based on ball grid array (BGA) packaging technology for 5G millimeter wave new radio (NR) FR2 band application. Based on the low-cost FR-4 substrate and single-layer configuration, the patch antenna achieves an ultra-low cost, which is attractive for large-scale 5G millimeter-wave array applications. Parasitic patches are added to the antenna to obtain broadband impedance bandwidth. To further reduce the antenna size and eliminate bulky connectors, solder balls are added to form a BGA package with connectorless interconnects. Consequently, the proposed antenna element achieves a compact size of 5.2 mm × 3.2 mm × 1.4 mm. Antenna elements and 1 × 8 array prototypes have been fabricated and verified. The measurement results show that the proposed antenna element has a -10 dB bandwidth of 56.1% (20-35.6 GHz), fully covering the 5G millimeter wave n257 (26.5-29.5 GHz), n258 (24.25-27.5 GHz), and n261 (27.5-28.35 GHz) bands. The maximum realized gains of the antenna elements and the 1 × 8 array prototype are 7.2 dBi and 13.9 dBi, respectively.

Frequency- and Pattern-Reconfigurable Antenna Array With Broadband Tuning and Wide Scanning Angles

A frequency and pattern reconfigurable 1 × 4 array is analyzed and designed, which consists of a reconfigurable feed network, twelve rectangular parasitic patches, and four octagonal patch antennas. Characteristic mode analysis is used to study the radiation characteristics of the proposed element antenna. By changing the on-off states of eighteen p-i-n diodes loaded in feed network, different combinations of initial current phase are obtained to realize the reconfiguration of five radiation states. By loading varactor diodes and parasitic patches, frequency reconfigurability is achieved. The measured result shows that the array pattern can be discretely switched in the directions of 0°, ±15°, ±25°, ±30°, and ±55°. The tunable overlapped -10 dB impedance bandwidth is 3.54-4.46 GHz for the five radiation patterns. The maximum gain reaches 7.67 dBi and the overlapped relative bandwidth of five radiation states is more than 22%.

Broadband high‐gain low‐temperature cofired ceramic substrate integrated cavity antenna array based on high‐order mode for W‐band applications

AbstractA broadband substrate integrated cavity (SIC) antenna array based on high‐order mode is proposed for low‐temperature cofired ceramic (LTCC) integrated systems in W‐band. To improve the gain of antenna element, a large SIC is adopted to work in high‐order mode, which also avoid using excessive vias and reduce the process complexity. Two parasitic patches are loaded on the high‐order mode SIC to remove the reverse E‐field in the open aperture, leading to a high‐gain broadside radiation. The high‐order‐mode SIC antenna element is fed by high‐order TE20‐mode substrate integrated waveguide (SIW), rather than regular TE10‐mode SIW. The simplified feeding network with TE20‐mode SIW is also designed with wideband performance, further enhancing the fabrication robustness of antenna array. To validate the proposed high‐order mode‐based antenna element and feeding network, a W‐band 2 × 4 antenna array is designed as an example using LTCC technology. The measured return loss is better than 10 dB from 81.1 to 98.1 GHz (19% bandwidth) with a maximum gain of 18.3 dB at 94 GHz. The proposed antenna array has great potential in millimetre‐wave and terahertz LTCC integrated applications.

A 22–28 GHz Polarization-Reconfigurable Flat-Panel 8 × 8 Tx/Rx Phased Array Antenna With Uniquely Arranged Novel Radiating Elements for CubeSat Communication

In this paper, a wideband (22-28 GHz), polarization reconfigurable, flat panel, 8x8 transmit (Tx)/receive (Rx) phased array antenna (PAA) is proposed. The array offers a realized gain of 22-23 dBi/dBic in the broadside direction and scans to approximately ±50° while maintaining 3dB gain drop/scan loss, low cross-polarized fields, and axial ratio (AR) below 3dB (in case of circular polarization (CP)) over the entire bandwidth within the given scan range. By utilizing the amplitude and phase control mechanism of the Radio Frequency Integrated Circuits (RFICs) employed for the beamforming network (BFN), each single radiating element of the array can work in four polarization cases such as horizontal (X-), vertical (Y-), left-hand circular and right-hand circular polarizations. The single element is a novel stacked patch configuration with L-shaped stubs at the two opposite corners of the driven patch and stubs on radiating edges of both the driven and parasitic patches. The radiator offers a wideband performance in addition to resolving the poor isolation between the two ports, thereby improving the cross-polarized fields and AR over the entire bandwidth. The radiating elements are arranged in a unique way in the array such that the benefit of element mirroring is achieved during the dual linear cases, whereas the benefit of sequential rotation of elements is achieved in dual CP cases, which further improves cross-polarized fields and AR. The simulated results are validated through the measurement results for a fabricated PAA prototype for the scanned radiation patterns for all four polarizations in receive mode, antenna gain-to-noise temperature (G/T) in receive mode, and effective isotropic radiated power (EIRP) in transmit mode.

A Flat-Panel 8 × 8 Wideband K-/Ka-Band Dual Circularly Polarized Phased Array Antenna for CubeSat Communications

A novel flat-panel 8×8 wideband dual circularly polarized electronically-scanned phased array antenna is proposed, which covers the satellite communications bands of 22.55–23.55 GHz and 25.5–27.5 GHz. A circularly polarized stacked microstrip patch antenna is used as the element radiator with a structural modification on the parasitic patch to minimize gain variation. Since the axial ratio (AR) bandwidth of the element radiator is inherently narrow, sequential rotation is employed to yield a wide AR bandwidth while forming the 2×2 subarray, which is then used as a building block to construct the larger 8×8 phased array. The phased array has a simulated scan range of ±51°, ±46° and ±36° at 23 GHz, 24 GHz and 26.5 GHz, respectively, assuming ≤3-dB scan loss and AR. A beamforming network (BFN) is integrated within the stackup of the phased array that comprises a commercially available silicon beamforming chip. This facilitates beam steering through the independent control of the input amplitudes and phases of the individual element radiators. The practical effects of the BFN on the scanning performance of the 8×8 phased array is studied, which is found to slightly degrade the scan ranges. Finally, experiments were performed on the fabricated prototype, and the measured scan data showed good correspondence with their simulated counterparts with >41° and 35° scan ranges (in +θ direction) at 24 GHz and 26.5 GHz, respectively. The corresponding EIRp and G/T of the 8×8 phased array are also estimated through measurements.

Broadband Circularly-polarized Crossed-dipole Antenna with Good Gain Stability

A broadband Circularly Polarized (CP) cross-dipole antenna with the merit of stable gain is proposed. The designed antenna consists of crossed dipoles, parasitic patches, reflectors, and vertical parasitic plates. By adding parasitic patches and parasitic plates, the circular polarization performance of the antenna is significantly improved. Furthermore, the gain value becomes stable in the entire operating frequency band by modifying the structure of the parasitic plates. The final dimension of the presented antenna is 0.76λ0 X 0.76λ0 X 0.28λ0 (λ0 is the wavelength at the center frequency point in the circularly polarized working frequency band). The measured results depict that the Impedance Bandwidth (IBW) is 80.8% (2.03GHz~4.78GHz) and the Axial Ratio Bandwidth(ARBW) is 68.5% (2.35GHz~4.8GHz). Stable gain values, ranging from 6dBic to 7.5dBic, are obtained in the working frequency band, and the average gain can reach 7dBic.

1-Bit Hexagonal Meander-Shaped Wideband Electronically Reconfigurable Transmitarray for Satellite Communications

This paper proposes a hexagonal meander-shaped wideband electronically reconfigurable transmitarray (HMRTA) at Ku band for satellite communications and radar applications. The proposed transmitarray offers high gain, low profile, and wideband characteristics with beam-scanning and beam-forming features. The cascaded structure is a low-profile and compact transmitarray. The transmitter (Tx) layer has an angular hexagonal patch with a meandered shape and resonating parasitic patches to enhance the bandwidth. The receiver (Rx) layer comprises a two-part hexagonal receiver patch and a dual ring impedance-matching receiver layer. The current reversal phenomena have executed the 180° phase shift by integrating two diodes in opposite directions. The measured results of a unit cell achieve a minimum insertion loss of 0.86 dB and 0.92 dB for state I and state II. The maximum insertion loss is 2.58 dB from 14.12 GHz to 18.02 GHz and is about 24.83% at 16.5 GHz. The full-wave simulations of a 20 × 20 space-fed reconfigurable transmitarray were performed. Good radiation patterns at all scanning angles of two principal planes are achieved, and the cross-polarization level remains less than −20 dB. The simulated 3 dB gain fluctuation bandwidth of the array is 15.85~18.35 GHz, and the wideband characteristics are verified. The simulation results show that the array can perform beam scanning ±60° in the elevation (y-z) plane and obtain the beam-scanning characteristics for ±60° in the Azimuth (x-z) plane.

Wideband Dual-Polarized Differential-Fed Filtering Microstrip Patch Antenna with High Suppression and Wide Stopband

This paper presents a wideband dual-polarized filtering antenna with high suppression level and wide stopband. In the proposed antenna, the driven patch operates in a TM10 mode with an inherent radiation null caused by a higher mode TM12. Four dual-strip structures connected with the feeding probes are placed below the driven patch to achieve the capacitive coupling, thus resulting in a low-frequency radiation null with a sharp roll-off rate. The introduction of the parasitic patch and strips generates an in-band resonance and two high-frequency radiation nulls, which widens the upper stopband. Four slots are etched on the driven patch to excite the third resonance, thus achieving the wide operation band. The prototype of the proposed antenna is fabricated. With four controllable radiation nulls, the out-of-band suppression levels are above 29 dB in low-frequency band greater than 1 GHz and above 21 dB in high-frequency band up to 7 GHz, respectively. Due to the three in-band resonances, a wide impedance bandwidth of 2.93-3.96 GHz with a fractional band of 30% is obtained. With the rotational symmetry structure driven by differential probes, the proposed dual-polarized antenna has a cross-polarization ratio better than 28 dB, a high polarization isolation above 43 dB, and a good peak gain about 9.9 dBi.

A Wideband Dual-Circularly Polarized, Simultaneous Transmit and Receive (STAR) Antenna Array for Integrated Sensing and Communication in IoT

This article presents a novel 5.8-GHz ISM-band dual-circularly polarized (CP) simultaneous transmit and receive (STAR) common-aperture antenna array (CAAA) for integrated sensing and communication (ISAC) in Internet of Things (IoT). A new near-field cancellation technique based on differential feeding and geometrical symmetry is proposed for dual-CP to realize high TX/RX isolation. In addition, a high-impedance surface is introduced to further improve the TX/RX isolation. Furthermore, the parasitic patches are added to enhance the gain and isolation bandwidth (BW). The simulation results demonstrate that the proposed CAAA possesses the merits of high isolation (up to 67 dB), wide isolation BW (better than 40 dB for 240 MHz BW), high gains (up to 10/10.5 dB for right-hand CP (RHCP)/left-hand CP (LHCP)), wide 1-dB gain BWs (better than 230/350 MHz BW for RHCP/LHCP), and low-axial ratios (lower than 1.4 dB). The designed CAAAs are fully characterized and the experimental results meet the simulation very well. For the first time, systematic validations for both wireless communication and radar sensing have been thoroughly carried out by integrating the proposed CAAA in the custom-designed full-duplex radio system. The experimental results not only prove the validity of the design methodology but also the feasibility of employing the proposed CAAA for ISAC, which indicates potential applications in IoT era.

Analysis of Super-Solar Integrated Patch Antenna for Sub-6 GHz and Beyond 6 GHz Millimeter Wave 5G Applications

This article describes a new compact parasitic patch-loaded transparent patch antenna with a copper ground plane for wireless-fidelity (Wi-Fi) and 5thgeneration (5G) millimeter-wave (mm-wave) applications. The proposed antenna uses two rectangular parasitic patches with a rectangular main radiation patch. The L-shaped strips are also added to the main radiation patch and one of the rectangular parasitic patches to cover both the sub-6 GHz and beyond 6 GHz mm-wave 5G frequency spectrums. The same transparent patch antenna with a solar ground plane is built, and its effect is parametrically studied alongside the integration of a polycrystalline silicon solar cell. The proposed antennas with a dimension of 42x30x2 mm23 are fabricated and experimentally validated for impedance and radiation characteristics. In terms of impedance bandwidth, the proposed copper ground plane antenna offers 36.89% (5.04-7.32 GHz), 5.15% (14.35-15.11 GHz), 6.23% (27.08-28.79 GHz), and 21.34% (31.64-39.81 GHz). The solar cell serves as both a photovoltaic generator and the ground plane of the transparent antenna. The same radiating patch with a solar ground plane offers impedance bandwidth of 36.03% (4.47-6.56 GHz), 14.4% (9.6-11.12 GHz), 2.55% (22.14-22.71 GHz), and 27.9% (28.79-39.05 GHz) for 5G applications.

Circularly polarized edge‐placed printed monopole antenna using theory of characteristic modes

AbstractThis article presents a method of using modal analysis to characterize the circular polarization (CP) performance of a printed monopole antenna. The radiator and feedline are positioned on the edge of the substrate and fed accordingly at the edge, and a modified ground plane is employed. The complete antenna without excitation is analyzed using characteristic mode theory to provide physical insight into its CP operation. The modal analysis proves that several nearly orthogonal modes can be generated at certain frequencies with orthogonal phase differences as well. The axial ratio (AR) corresponds to the modal analysis which proves the validity of the modal analysis. An axial ratio bandwidth from 3.1 to 6.2 GHz (66. 7%) is achieved within an S11 bandwidth of 2.6–11 GHz (123.5%). The proposed antenna is compact with stable radiation patterns, easy to design, and fabricate without inserting parasitic patches or inserting slots on the antenna.

Design of a Taiji-like Dual-band Microstrip Patch Antenna Loaded with Bagua Parasitic Patch

This study proposes a Taiji-shaped microstrip patch antenna without affecting its size and design complexity. The radiation patch adopts a Taiji-like shape design, and the traditional Chinese Bagua-shaped parasitic element is loaded on the periphery of the radiation patch on the surface of the dielectric substrate to optimize the impedance matching further and improve the gain. The software HFSS15.0 is used to simulate the antenna and compare the results. The results show that the antenna achieves dual-band characteristics at 2.45GHz and 5.04GHz, has an impedance bandwidth of 110MHz and 250MHz, and has a positive gain of 7.13dB. The proposed antenna is suitable for the field of wireless communication.

Reconfigured antenna with switchable polarization for S Band Wireless applications

This article presents a polarization-switchable Microstrip Patch Antenna (MPA) that can be flexibly reconfigured. There are little parasitic patches connected to the corners of an MPA's circular patch as a radiator. The PIN diodes have made contact with O-shaped parasitic patch elements to form the circular patch. When the truncated corners are changed, enhanced the impedance bandwidth and axial ratio bandwidth has been obtained. 3.24 GHz is a resonant frequency for an impedance match (S11 less than 10dB) and for an axial ratio (AR less than 3 dB). The antenna's ability to transition between left- and right-handed circular polarizations (LHCP and RHCP) was verified by comparison of simulated and measured results observed. Vector Network Analyzer has also been used to evaluate the anticipated MPA under high RF strength in an anechoic room. Thus, the 5G networks and their related applications have been shown to work with these observed characteristics.

Wideband circularly polarized microstrip-slot antenna with parasitic elements

ABSTRACT In this letter, a new wideband circularly polarized (CP) slot – microstrip patch antenna (SPMA) is elaborated. The proposed antenna consists of four crown patches as parasitic patches, an L-shaped crown slot etched into the ground plane as a parasitic slot, and a circular loop sequential rotating feeding structure (SRFS) as a driven element. First, four crown patches are used to stimulate a CP resonance. Second, the L-shaped crown slot is applied to excite an additional CP resonance. After that, the CP bandwidth of the antenna could be enhanced by combining these CP resonant modes. The measured results demonstrate that the antenna features a wide CPBW of 14.8% (5.30–6.15, 5.725 GHz), which has a potential application value in the WIFI (5.85–5.925 GHz) bands and the wireless local area network ITS (5.8 GHz) and (5.725–5.85 GHz).