Stable High Gain Research Articles

Advanced Metamaterial-Integrated Dipole Array Antenna for Enhanced Gain in 5G Millimeter-Wave Bands

A metamaterial-based non-uniform dipole array antenna is presented for high gain 5G millimeter-wave applications with a wideband characteristic. Initially, a non-uniform dipole array is designed on a 0.202 mm thick Rogers RO4003C substrate, offering a wide operating bandwidth ranging from 23.1 GHz to 44.8 GHz. The dipole array antenna emits unidirectional end-fire radiation with a maximum gain of 8.1 dBi and an average gain of 6.7 dBi. Subsequently, to achieve high gain performance, a 5 × 7 metamaterial structure is designed in the direction of the antenna radiation. The implemented metamaterial structure is optimized for the operating frequency, enhancing the directivity of the antenna radiation and resulting in a gain increment of more than 3 dBi compared to the dipole array alone. The developed metamaterial-integrated dipole array antenna offers an operating bandwidth (S11 < −10 dB) of more than 21 GHz (63.92%), ranging from 23.1 GHz to 44.8 GHz, covering the most commonly used 5G millimeter-wave frequency bands (n257, n258, n259, n260, and n261). Furthermore, the presented antenna yields a stable high gain with a peak gain of 11.21 dBi and a good radiation efficiency of more than 64%. The proposed antenna is an excellent option for millimeter-wave 5G systems due to its overall properties, particularly its high gain and end-fire radiation characteristics, combined with a wide operating bandwidth.

A stable high-gain cavity-stacked antenna array with compact high-order mode fed for W-band applications

This paper presents a W-band stable high gain 2 × 2 cavity-backed slot antenna array fed by compact high-order mode substrate-integrated cavity (SIC) with substrate-integrated waveguide (SIW) technology. The antenna element incorporates a 2 × 2 subarray of cross-shaped slots, excited by a high-order mode (TE220) SIC, ensuring uniform amplitude and balanced phase to achieve stable high-gain and high efficiency. Moreover, an additional SIW cavity is stacked above the 2 × 2 cross-shaped slots, incorporating a rectangular slot etched on the surface of the SIW cavity for radiation to further enhance the gain. This novel architecture yields a gain enhancement of 2.6 dBi compared to the traditional unstacked SIW cavity antenna. A prototype antenna array, consisting of 2 × 2 radiation elements and a low-loss 1-to-4 SIW power divider integrated with waveguide (WG) to SIW transition, is designed and fabricated in standard PCB technology. The measured results exhibit a −10 dB impedance bandwidth range from 91 to 97 GHz, a peak gain of 18.5 dBi, and a peak aperture efficiency of up to 78 %.

A Simple Cylindrical Dielectric Resonator Antenna Based on High-Order Mode with Stable High Gain

A Simple Cylindrical Dielectric Resonator Antenna Based on High-Order Mode with Stable High Gain

Dual-Polarized Wide-Beam Antenna Array With Stable High Gain for WiFi-6E (U-NII 6-GHz) Communications

Dual-Polarized Wide-Beam Antenna Array With Stable High Gain for WiFi-6E (U-NII 6-GHz) Communications

Millimeter-Wave 1-D Wide-Angle Scanning Pseudo-Curved Surface Conformal Phased Array Antennas Based on Elongated Planar Aperture Element

To perform wide-angle scanning while maintaining a planar low profile, we propose a new kind of millimeter-wave (mmWave) planar phased array antenna using inclined beam elements to imitate a curved surface conformal (CSC) array, called a pseudo-curved surface conformal (PCSC) phased array antenna. We present the concept of our PCSC phased array and then design an elongated planar aperture antenna (EPAA) element, achieving stable high broadside gain and wide beam on the scanning plane within a wide bandwidth. Then, by introducing asymmetries to the EPAA element, the beam inclination of the EPAA element can be adjusted. Accordingly, we use EPAA elements with different beam inclinations to form a 1 × 4-element 1-D wide-angle scanning PCSC phased array antenna. We design, fabricate, and measure a prototype of our proposal, with measured results showing that the proposed design has a 3 dB gain variation across a scanning range of more than ±62° (and as high as ±68°) within the 5G mmWave band (24.25 to 29.5 GHz), which is about ±10° better than its traditional counterpart.

A comparative analysis of GaN and InGaN/GaN coupling channel HEMTs on silicon carbide substrate for high linear RF applications

In this work, we report comparative analysis of stable transconductance and high gain linearity for AlGaN and InAlN barrier-based HEMTs using an InGaN/GaN coupling channel with AlGaN back-barrier on Silicon carbide (SiC) substrate. The proposed InGaN/GaN coupling channel HEMTs showed flat transconductance and suppressed gm derivatives. LG 55 nm AlGaN (InAlN)/GaN conventional HEMTs showed 2.9 (3.8) A/mm of IDS, 0.59 (0.62) S/mm of transconductance (gm), 51.86 (27.42) V of VBR, 212 (233) GHz of fT, 242 (255) GHz of fMAX. Whereas, Lg 55 nm InGaN/GaN coupling channel-based AlGaN (InAlN) HEMT showed 3.3 (5.1) A/mm of IDS, 0.67 (0.71) S/mm of transconductance (gm), 53.12 (41.25) V of VBR, 251 (273) GHz of fT, 262 (283) GHz of fMAX. Moreover, high gate voltage swing (GVS) and larger OIP3 of proposed coupling channel HEMTs are suitable candidates for next-generation high linear RF applications.

A Low-Profile, Circularly Polarized, Metasurface-Based Antenna With Enhanced Bandwidth and Stable High Gain

A low-profile circularly polarized (CP) metasurface-based (MS-based) antenna with enhanced axial-ratio bandwidth (ARBW) and stable high gain is developed. The developed antenna has a stacked layout with the MS containing 3 × 3 patch lattices, which are placed above a custom-designed driven element. The driven element comprises a patch with an etched slot and a parasitic ring strip with shorting pins, which can excite the MS to generate multiple resonances and three AR minimum points, thus resulting in enhanced ARBW and stable high gain. Finally, an antenna prototype is designed to confirm the simulation results. The experimental (simulated) results demonstrate that the MS-based antenna is low-profile: 0.03 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> corresponds to the operating central frequency at 2.63 GHz, achieving a −10 dB fractional bandwidth (FBW) of 20.48 (19.81)%, and 3 dB ARBW of 10.2 (11)% along with a stable gain of 8.1–8.8 (8.0–9.2) dBic, respectively.

Stable High-Gain Linearly and Circularly Polarized Dielectric Resonator Antennas Based on Multiple High-Order Modes

Dielectric resonator antennas (DRAs) under high-order multiple-modes resonator (MMR) for stable high gain are proposed in this communication. The approach is to implement slot cuts on the surface of DR for reconstructing the electric field distribution of high-order resonance modes. In this way, the sidelobes are reduced and two high-order modes are reallocated to construct a continuous wide band. Various MMR configurations were proposed in this work. First, a DRA operating in TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {x}}_{031}$ </tex-math></inline-formula> and TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {x}}_{051}$ </tex-math></inline-formula> modes is proposed with a pair of loaded slots to realize a fractional bandwidth (FBW) of 26% and a stable gain as high as 8.3 dBi within the desired passband. Second, a DRA with TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {x}}_{051}$ </tex-math></inline-formula> and TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {x}}_{071}$ </tex-math></inline-formula> modes is developed by introducing two pairs of slots, and an impedance FBW of 12.8% and a stable gain as high as 11 dBi are achieved. Third, three pairs of slots are introduced to the DRA with TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {x}}_{091}$ </tex-math></inline-formula> and TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {x}}_{0,11,1}$ </tex-math></inline-formula> modes, and an impedance FBW of 6.4% and a stable antenna gain as high as 12.3 dBi are obtained. At last, a circularly polarized (CP) DRA array with four proposed linearly polarized (LP) DRA elements is designed with an impedance bandwidth of 51.8%, a 3 dB axial-ratio (AR) FBW of 32%, a peak gain of 13.89 dBic, and a 1 dB gain bandwidth of 19.9%.

Polarization Reconfigurable High-Gain Fabry–Perot Cavity Antenna

We propose an innovative polarization reconfigurable high-gain Fabry–Perot cavity (FPC) antenna. The antenna can electrically select its polarization among three linear polarization (LP) modes of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$x$ </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">$y$ </tex-math></inline-formula> -, and 45°-direction with stable high gain. To achieve these properties, we devise a novel polarization conversion partially reflective surface (PCPRS) as a superstrate. The PCPRS plays two crucial roles simultaneously; it reconfigures antenna polarization and maintains high gain using an FP resonance between the PCPRS and a ground plane. The FP resonance, which is the key point in our antenna design, is essential to maximize both antenna gain and polarization reconfigurability. Therefore, in order to stably achieve the FP resonance for all three polarization modes, we have designed the PCPRS to keep its reflection behavior as constant as possible for all LP modes. To the best of our knowledge, this is the first FPC antenna introducing a partially reflective surface (PRS) which also functions as an active polarizer. Consequently, the proposed antenna attains remarkable polarization conversion performance with higher than 20 dB cross-polarization suppression level for all polarization modes. Moreover, in all modes, our antenna well maintains reasonably high gain of about 15 dBi with good impedance matching properties. Good agreement between measurements and simulations proves the validity of our design approach.

Wideband single‐layer patch antenna with stable high gain using characteristic mode analysis

A low-profile single-layer patch antenna is proposed for bandwidth enhancement and stable high gain simultaneously. Firstly, coplanar parasitically coupled patches are introduced on two edges of the main driven patch to generate new resonant modes. The mutual compensation of modal electric energy and magnetic energy and the combination of modes lead to wideband performance based on characteristic mode analysis (CMA). Secondly, due to odd mode with unstable gain at high frequency, metallised vias are installed in the parasitic patches. Therefore, the symmetrical TM01 mode of parasitic patches is reshaped to the TM10 mode, and three in-phase TM10 modes are connected in parallel to generate stable high gain. The CMA is utilised to guide the transformation of unwanted modal behaviours into desired modal states. The achieved impedance bandwidth for −10 dB is 13.7% (4.96–5.69 GHz) with a gain of 6.86–8.53 dBi over the operating bandwidth.

A BiCMOS frontend electronics chipset for the readout of the INO-ICAL RPC detector

This paper presents a BiCMOS voltage amplifier-based high-speed frontend electronics (FEE) chipset, designed in 0.35μm SiGe BiCMOS technology. This chipset comprises two ASICs, namely a quad voltage amplifier ASIC and an octal comparator ASIC. The two-chip FEE is designed for the readout of large area, single-gap, avalanche mode Resistive Plate Chamber (RPC) detectors of the Iron Calorimeter (ICAL) experiment of the India based Neutrino Observatory (INO). The use of a voltage amplifier-based FEE topology along with a separate comparator ASIC resulted in a stable high gain and high-speed FEE operation in the presence of a large number of detector channels. This FEE solution has a total amplifier gain of 74, overall timing precision of 140 ps (RMS), and power consumption of 25 mW/channel. It exhibits pixel-wise detector efficiency larger than 90% along with position- and time-resolution of 1 cm RMS, and 1 ns RMS, respectively, when used with a prototype INO-ICAL RPC detector of size 1.85 m × 1.75 m. Furthermore, the performance of the FEE is not affected by the presence of the magnetic field (1.3 T) used in the experiment.

Landstorfer Printed Log-Periodic Dipole Array Antenna With Enhanced Stable High Gain for 5G Communication

A novel wideband stable high-gain Landstorfer printed log-periodic dipole array (PLPDA) antenna loaded with zero-index metamaterials (ZIMs) is proposed for wireless communication system. Based on the Landstorfer-shaped method, the dipoles and ground of the PLPDA antenna are Landstorfer-shaped and strung together by feeding lines to form a novel Landstorfer PLPDA antenna, which obtains a gain enhancement compared with the PLPDA antenna. To further enhance both the antenna gain and gain flatness, a series of novel ZIM are added to the shorter end of the Landstorfer PLPDA antenna. As an example, four-element Landstorfer PLPDA antennas with/without ZIM are designed, implemented, and measured in Ka-band for 5G application. Compared with the original PLPDA antenna, the proposed Landstorfer PLPDA antenna exhibits a maximum gain enhancement of 2.2 dB within the operating band of 26.5–40 GHz. Loaded with ZIM, the antenna gain can be further improved by 0.5–1.9 dB with a measured gain flatness of 10.5 ± 0.5 dBi over the band of 25.7–40 GHz while the size of antenna keeping unchanged. The proposed antenna presents a stable high-gain performance in terms of the parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta G$ </tex-math></inline-formula> /BW ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta G$ </tex-math></inline-formula> is the gain variation, BW is the bandwidth) less than 0.07 within the whole Ka-band.

Design of a Dual-Linearly Polarized Endfire Antenna

In this article, a dual-linearly polarized endfire antenna is proposed with high gain and stable radiation patterns. A double-sided slot array antenna (DSSAA) and a corrugated rectangular metal strip (CRMS) are employed to realize vertical and horizontal polarization (HP), respectively. Omnidirectional radiation pattern is obtained by etching transverse slots on both sides of the top and bottom metallic plates of a cavity. Based on the double-sided slot antenna, a DSSAA is proposed and fed by an air-substrate parallel strip line (PSL) for stable endfire radiation patterns. Then, the top plate of the DSSAA is reused as a CRMS for HP and compact size. To verify this concept, an all-metal prototype was fabricated and measured. Both the simulation and experimental results show that the DSSAA and the CRMS could offer the highest endfire gains of 12.5 and 12.9 dB, respectively, within a footprint of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.47\lambda _{0} \times 0.72\lambda _{0} \times 0.13\lambda _{0}$ </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">$\lambda _{0}$ </tex-math></inline-formula> is the free-space wavelength at the center frequency). Moreover, an overlapping bandwidth of 7.6% is realized with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert S_{11}\vert &lt; -10$ </tex-math></inline-formula> dB, gain variation less than 3 dB. This work may provide useful references for designing dual-polarized endfire antennas with stable radiation patterns, high gain, and compact size.

Multibeam OAM Transmitarray With Stable Vortex Property Based on Bifocal Method

In this letter, a multibeam transmitarray carrying orbital angular momentum (OAM) is introduced to realize 1-D +/-30° beam coverage. A three-layer unit cell is designed to provide high-efficiency transmission and full 360° phase coverage. This unit cell consists of two orthogonal polarizers at the outermost layers and a polarization rotating patch in the middle layer. A feeding array is employed to illuminate the transmitarray. By combining bifocal principle with the method of OAM beam generation, the stability of steered OAM beams is improved compared to conventional single focal design. A five-beam protype producing -1 OAM mode is simulated, fabricated, and measured, realizing a +/-30° beam coverage with stable vortex property and high mode purity. The proposed design has advantages such as multi-OAM-beam, stable vortex property, wideband, high gain, and easy fabrication.

A 56–161 GHz Common-Emitter Amplifier with 16.5 dB Gain Based on InP DHBT Process

This paper presents a broadband amplifier MMIC based on 0.5 µm InP double-heterojunction bipolar transistor (DHBT) technology. The proposed common-emitter amplifier contains five stages, and bias circuits are used in the matching network to obtain stable high gain in a broadband range. The measurement results demonstrate a peak gain of 19.5 dB at 146 GHz and a 3 dB bandwidth of 56–161 GHz (relative bandwidth of 96.8%). The saturation output power achieves 5.9 and 6.5 dBm at 94 and 140 GHz, respectively. The 1 dB compression output power is −4.7 dBm with an input power of −23 dBm at 94 GHz. The proposed amplifier has a compact chip size of 1.2 × 0.7 mm2, including DC and RF pads.

Design of broadband circularly polarized THz antenna with stable radiation pattern for 6G communications

This paper presents a compact efficient and stable high gain broadside circularly polarized (CP) antenna using WR3 waveguide. Asymmetrical H-shaped slot arrays deployed on the broadside wall of the waveguide, suits the antenna for operating in the Sub THz range of frequencies. The designed antenna operates almost entire frequency range of WR3 waveguide from 227 GHz to 380 GHz with a return loss ≤ −10 dB roofing the WM834 band. The proposed antenna possesses a wide axial ratio bandwidth (ARBW) of 28.28 GHz spanning from 289.1 GHz to 317.38 GHz with persistent gain and exhibits a minimum axial ratio of 0.72 dB in the range of 296–309 GHz. Furthermore, the model attains a maximum directivity of 16.5 dBi and a peak gain of 16.1 dBi at 317 GHz with the first sidelobe level (SLL) of − 13.6 dB and radiation efficiency of 97.5% towards the broadside direction. Apart from the stable pattern in the CP band, beam scanning of the main lobe from 250 GHz to 340 GHz is also observed. The proposed antenna has been designed, simulated, and optimized using CST microwave studio and the results are validated using HFSS software.

Metantenna design with one‐dimensional holographic concept

In this paper, metasurface antenna (metantenna) with one-dimensional holographic concept is proposed and an example of producing 50° radiation beam angle at 16 GHz is taken to certify the metantenna operating principle. We first introduce one-dimensional holographic theory to simplify the metasurface design. By this means, compared with the traditional two-dimensional metantenna, the integral structure has fewer unit cells, simpler structure and the beam-tilt is achieved as well. Simultaneously, to feed the metasurface above efficiently, the tapered microstrip line is modified by adding a sloping metal strip as a plane-wave surface wave launcher, thus obtaining a smooth transition from Quasi transverse electromagnetic wave to transverse magnetic wave and a broad frequency band of impendence matching. A prototype is fabricated and tested at last. The measured radiation beam angle is 49° at 16 GHz, which approximates to the desired beforehand. On the other hand, this metantenna has a beam scanning angle of 24° to 63° from 13 to 17.5 GHz. The gain is about 13 to 15 dBi and the half power beam width is about 9° in the above frequency range. It has features of stable high gain, narrow beamwidth and high radiation efficiency.

Pin-Loaded Patch Antenna Fed With a Dual-Mode SIW Resonator for Bandwidth Enhancement and Stable High Gain

A pin-loaded patch antenna fed with a dual-mode substrate-integrated waveguide (SIW) resonator is proposed in this letter for enhanced bandwidth and stable high gain. The loading effect of shorting pins on quality factor of the radiator is investigated with characteristic mode analysis at first. As such, the pin location can be properly selected to enhance gain with the least negative effect on bandwidth. A SIW resonator operating in TE110 and TE120 modes is introduced to feed the patch through aperture coupling. The dual modes of SIW resonator increase the resonant order of the antenna with compact size, which significantly widens the bandwidth. Moreover, the undesired high-order mode is well suppressed with the proposed feeding scheme, which further contributes to steady radiation performance. Simulated and measured results demonstrate that the proposed patch antenna has obtained an enhanced bandwidth of 22% and stable high gain up to 11.9 dBi simultaneously.

Dual Band Notch, Compact, Low profile Hybrid Ultra Wideband RDRA

This paper presents a novel, compact Ultra Wide Band , Asymmetric Ring Rectangular Dielectric Resonator Antenna (ARRDRA), which is a unique combination of Thin Dielectric Resonator (DR), Fork shape patch and defective ground structure. The base of the proposed antenna is its Hybrid structure, which generates fundamental TM, TE and higher order modes that yields an impedance bandwidth of 119%. Proposed antenna provides a frequency range from 4.2 to 16.6 GHz with a stable radiation pattern and low cross polarization levels. Peak gain of 5.5 dB and average efficiency of 90% is obtained by the design. Antenna is elongated on a FR4 substrate of dimension 20 x 24x 2.168 mm3 and is particularly suitable for C band INSAT, Radio Altimeter, WLAN, Wi-Fi for high frequencies. Ease in fabrication due to simplicity, compactness, stable radiation pattern throughout the entire bandwidth are the key features of the presented design. Inclusion of Defective ground structure and asymmetric ring not only increases the bandwidth but also stabilize the gain and efficiency due to less surface current. Presented design launch an Ultra Wide Band antenna with sufficient band rejection at 4.48-5.34 and 5.64-8.33 GHz with stable radiation pattern and high gain.

A Wideband Slotted Spherical Waveguide Antenna Based on Multi-Mode Concept

A wideband slotted spherical waveguide antenna based on the multi-mode concept is presented. The proposed design starts from a metallized spherical cavity fed by a rectangular waveguide. Then, two groups of slots are symmetrically cut on the shell. By suitably choosing the slot dimensions and locations, four radiation modes can be excited in a single radiator and merged with each other, resulting in a wideband radiation characteristic. To verify this, a prototype is designed and fabricated using stereolithography apparatus to achieve a light weight. As the measured fractional bandwidth (FBW) of the proposed antenna can be increased to 70.1% while maintaining stable radiation patterns and high gain, a simple and effective design of wideband slotted waveguide antennas with good radiation characteristics can be validated.