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In this paper, a novel CPW-fed dual-band on-chip antenna (OCA) by introducing a crossed bowtie shaped defected ground structure (CB-DGS) in one of the intermediate layers of the CMOS layout is proposed. In general, a CPW fed OCA has its ground plane on the same plane containing the antenna. However, in this work, a DGS is introduced in one of the intermediate layer using through silicon vias to obtain dual band characteristics with improved gain performance of the antenna. A 10 dB operating band of 9 GHz (2.25–11.75 GHz) is achieved by employing meandered loop miniaturization technique on the antenna designed on top CMOS layer, wherein the introduction of DGS layer enforced a comparatively less stop band at the middle of the operating band and the resultant structure offered a dual-band resonance characteristic at 3.1 GHz and 10.4 GHz. Here, the intermediate DGS layer between the top-layered antenna and silicon wafer reduces the substrate loss by preventing the coupling of the electromagnetic radiation with the substrate and enhances the antenna gain significantly at both the resonance frequencies respectively by + 16.01 dB and + 12.7 dB. A prototype of the proposed antenna structure is fabricated and the obtained simulated result is validated through experimental measurement. [ABSTRACT FROM AUTHOR]

Summary: In this paper, gain improvement and impedance matching of THz patch antenna by using semicircular slot and modified ground plane are discussed. The proposed antenna consists of a simple rectangular patch configuration. The novelty of the proposed antenna is its semicircular slot, and modified ground structures are used to enhance the gain and impedance matching of the proposed antenna. Design evolution along with parametric studies is also offered in this paper along with the return loss comparisons. Surface current distributions that are presented for the validation of proposed antenna's operation are controlled by the slots. The effect of slots on performance of the proposed antenna is also offered in this paper. The proposed antenna is designed and simulated on CST software. The proposed antenna occupies a compact area of 100 × 150 × 10 μm3, which in terms of wavelength can be given by 0.33 λ0× 0.5 λ0× 0.03 λ0, where λ0 is the free space wavelength at 1 THz. The proposed antenna has a resonant frequency of 1 THz with a realized peak gain of 8.87 dBi and efficiency of 87%, respectively. The proposed antenna can be a suitable candidate for 1‐THz applications. [ABSTRACT FROM AUTHOR]

This paper presents a 1 × 4 linear antenna array working at 28 GHz for 5G communication systems. The proposed array employs four rectangular slotted antenna elements fed by a 1 × 4 T-power divider. An artificial magnetic conductor (AMC) layer is placed below the array for increasing the radiation intensity and improving overall array gain. The measured impedance bandwidth of the proposed array with (|S11| < −10 dB) is extended from 25.36 to 26.03 GHz (with a bandwidth of 0.67 GHz) and from 26.75 to 28.81 GHz (with a bandwidth of 2.06 GHz). The proposed array design exhibits a measured gain value that varies between 11.8 dBi and 13.1 dBi within the operating bands and reaches 13.1 dBi at 28 GHz. The proposed array achieves a radiation efficiency of 83.05%, and a front-to-back ratio ranging between 15 and 20 dB across the operating frequency band. The array is fabricated and tested with good matching between the simulated and tested outcomes. The improved performance of the array makes it a suitable candidate for 5G new radio (NR) communications. [ABSTRACT FROM AUTHOR]

In this paper, a wideband high gain Vivaldi antenna based on spoof surface plasmon polaritons metamaterial for radio astronomy application is proposed. The height of the spoof surface plasmon polaritons structures fits the exponential function, thus the structure is named exponential spoof surface plasmon polaritons (ESSPP) metamaterial. With the exponential heights, the ESSPP metamaterial could correct the phase difference in a wide band, the gain is improved in the wide frequency range from 3 GHz to 9 GHz, and the proposed antenna exhibits stable radiation patterns with an average gain of 10.6 dBi. [ABSTRACT FROM AUTHOR]

A wideband frequency reconfigurable antenna based on active artificial magnetic conductor (AAMC) surface is proposed with improved gain. The AAMC element consists of a composite polygon‐rectangle‐ring with five patches and a cross‐strip inside. A reverse‐bias varactor is inserted between the ring and ground plane to make the in‐phase reflection frequency bands adjustable. A dipole is placed above the AAMC surface which is composed of 5 × 5 unit cells. The measured results show that the reconfigurable frequency ranges from 1.64 to 4.16 GHz while maintaining the radiation patterns stable. Moreover, the peak gain reaches 10.65 dBi at 3.5 GHz. [ABSTRACT FROM AUTHOR]

This article demonstrates a compact wideband four-port multiple-input-multiple-output (MIMO) antenna system integrated with a wideband metamaterial (MM) to reach high gain for sub-6 GHz new radio (NR) 5G communication. The four antennas of the proposed MIMO system are orthogonally positioned to the adjacent antennas with a short interelement edge-to-edge distance (0.19λmin at 3.25 GHz), confirming compact size and wideband characteristics 55.2% (3.25–5.6 GHz). Each MIMO system component consists of a fractal slotted unique patch with a transmission feed line and a metal post-encased defected ground structure (DGS). The designed MIMO system is realized on a low-cost FR-4 printed material with a miniature size of 0.65λmin × 0.65λmin × 0.02λmin. A 6 × 6 array of double U-shaped resonator-based unique mu-near-zero (MNZ) wideband metamaterial reflector (MMR) is employed below the MIMO antenna with a 0.14λmin air gap, improving the gain by 2.8 dBi and manipulating the MIMO beam direction by 60°. The designed petite MIMO system with a MM reflector proposes a high peak gain of 7.1 dBi in comparison to recent relevant antennas with high isolation of 35 dB in the n77/n78/n79 bands. In addition, the proposed wideband MMR improves the MIMO diversity and radiation characteristics with an average total efficiency of 68% over the desired bands. The stated MIMO antenna system has an outstanding envelope correlation coefficient (ECC) of <0.045, a greater diversity gain (DG) of near 10 dB (>9.96 dB), a low channel capacity loss (CCL) of <0.35 b/s/Hz and excellent multiplexing efficiency (ME) of higher than −1.4 dB. The proposed MIMO concept is confirmed by fabricating and testing the developed MIMO structure. In contrast to the recent relevant works, the proposed antenna is compact in size, while maintaining high gain and wideband characteristics, with strong MIMO performance. Thus, the proposed concept could be a potential approach to the 5G MIMO antenna system. [ABSTRACT FROM AUTHOR]

A simple structured, compact ultra-wideband (UWB) circular disk monopole antenna of dimension 35 × 30 × 0.8 mm3 that offers wide bandwidth from 2.64 to 9.36 GHz with sharp triple notch bands at 3.28–3.84, 5.08–5.44, and 5.62–6.06 GHz is integrated to the single-layer UWB frequency selective surface (FSS) that has unit cell dimension of 0.1136λL × 0.1136λL only where λL signifies the lower band-edge of UWB. Sharp triple notches are employed by embedding split-ring slot on circular patch and implanting dual circular split-ring resonator pairs at the backside of feed. Addition of FSS layer does not affect the antenna impedance band and offers significant antenna gain improvement by 2–4 dBi in the pass bandwidth with maximum gain of 8 dBi at 8.5 GHz. The antenna also provides high average radiation efficiency of 80%, improved radiation in the broadside direction and consistent group delay response in its pass band when integrated to the FSS layer. Working capability of proposed antenna-FSS structure is evaluated in proximity of soil test bed by keeping thin aluminum sheet at different buried levels. Adequate VSWR profile, linear transfer function response, and consistent group delay response in pass band ensure the eligibility of proposed antenna to work for ground penetrating radar. [ABSTRACT FROM AUTHOR]

In this paper design and performance comparison of arrays of circular, square and hexagonal meta-material structures for wearable applications have been carried out. Meta-material structures are based on the artificial magnetic structures such as Split Ring Resonators (SRR). Design and analysis of this antenna at the operating frequency of 2.4 GHz (ISM band) is done by using the Ansoft HFSS software. It consists of two microstrip lines with the slits in between them and both the shapes are made like a C-shape by forming the gaps at opposite sides of each ring. The substrate for unit cell of meta-material is polyester which has width and length of 10 mm. It is also concluded from the simulation results that the antenna offered good gain with meta-material structure in comparison with the non-meta-material structure. Meta-material structures have good radiating effects as it has negative electromagnetic properties. [ABSTRACT FROM AUTHOR]

Substrate integrated waveguide (SIW) technology that combines 3D and 2D structures has been successfully utilized due to its notable advantages, including in its application to H-plane horn antennas. As this type of antenna is commonly constructed on thin substrates, the E-plane radiation pattern is always wide, thereby limiting the achievable gain performance. In this work, we propose an approach that incorporates 3D printed horns on a prefabricated SIW H-plane horn antenna to successfully narrow the E-plane radiation pattern, thereby improving the gain performance. The proposed E-plane horn is designed at the aperture of the original H-plane horn, providing a smooth and continuous wave transition from the thin substrate to the end-fire direction. This approach improves the directional radiation performance significantly and reduces fabrication time and associated difficulties as the parasitic structures are simply attached to the SIW horn, without the requirement of redesigning or refabricating the original antenna. From 20 to 25 GHz, an optimized prototype shows excellent performance. At 22.7 GHz, it exhibits 35° and 33° for the E- and H-plane half-power beamwidths (HPBWs), with corresponding side-lobe levels (SLLs) of −23 dB and −15 dB. The present research reveals that the proposed design presents high feasibility and a reduced demand for high-precision manufacturing processes at a lower cost, concomitantly providing an effective means to further improve on the radiation characteristics. [ABSTRACT FROM AUTHOR]