A parasitic patch loaded staircase shaped UWB MIMO antenna having notch band for WBAN applications.

A staircase-shaped quasi-fractal antenna is presented to meet the requirements of compact electronics operating in UWB or E-UWB spectrum. A conventional broadband monopole antenna is converted into UWB antenna utilizing three iterations of fractal patches. The resultant antenna offers wide impedance bandwidth ranges 2.3-17.8 GHz, having a notch band at 6.1-7.2 GHz. Afterwards, a two-port MIMO antenna is created by placing the second element orthogonally with an edge-to-edge distance of 8.5 mm, that is λ/15 where λ corresponds to free space wavelength at the lowest cut-off frequency. Hereafter, a meandered line-shaped stub is inserted to reduce the mutual coupling between closely spaced MIMO elements to less than -25 dB. As the intended application of the proposed work is On-body, Specific Absorption Rate (SAR) analyses are carried out at 2.4, 5.8 and 8 GHz, showing an acceptable range for both 1-g and 10-g averaged tissues standards. Moreover, various parameters of the MIMO antenna are studied, and a comparison is made between simulated and measured results as well as those of the state of the art.

A high bandwidth dimension ratio compact super wide band-flower slotted microstrip patch antenna for millimeter wireless applications.

A compact high bandwidth ratio (BDR) super wide band flower slotted micro strip patch antenna (SWB-FSMPA) for super wide band (SWB) applications is presented. The SWB-FSMPA is constructed on a FR-4 substrate having a size of 16 × 22 mm2. The SWB-FSMPA incorporates a 50 Ω tapered micro strip line and a rectangular beveled defected ground structure (RB-DGS). This design enables a simulation bandwidth from 3.78 to 109.86 GHz, allowing for coverage of various wireless applications such as WiMAX (3.3-3.6 GHz), 5G (3.3-3.7 GHz), WLAN (5.15-5.825 GHz), UWB (3.1-10.6 GHz), Ku- (12-18 GHz), K- (18-27 GHz), Ka- (27-40 GHz), V- (40-75 GHz), and W- (75-110 GHz) millimeter wave bands. The SWB-FSMPA antenna exhibits a gain that varies within the range of 3.22-7.23 dBi and a peak efficiency of 93.3 %. The SWB-FSMPA possesses a bandwidth ratio (BR) of 29.1:1, a BDR of 5284 in the frequency domain, a minimal group delay (GD) fluctuation of <0.48 ns, and a linear phase in the time domain, making it well-suited for SWB applications.

The Optimization and Analysis of a Triple-Fin Heterostructure-on-Insulator Fin Field-Effect Transistor with a Stacked High-k Configuration and 10 nm Channel Length.

The recent developments in the replacement of bulk MOSFETs with high-performance semiconductor devices create new opportunities in attaining the best device configuration with drive current, leakage current, subthreshold swing, Drain-Induced Barrier Lowering (DIBL), and other short-channel effect (SCE) parameters. Now, multigate FETs (FinFET and tri-gate (TG)) are advanced methodologies to continue the scaling of devices. Also, strain technology is used to gain a higher current drive, which raises the device performance, and high-k dielectric material is used to minimize the subthreshold current. In this work, we used stacked high-k dielectric materials in a TG n-FinFET with three fins and a 10 nm channel length, incorporating a three-layered strained silicon channel to determine the short-channel effects. Here, we replaced the gate oxide (SiO2) with a stacked gate oxide of 0.5 nm of SiO2 with a 0.5 nm effective oxide thickness of different high-k dielectric materials like Si3N4, Al2O3, ZrO2, and HfO2. It was found that the use of strained silicon and replacing only the SiO2 device with the stacked SiO2 and HfO2 device was more beneficial to obtain an optimized device with the least leakage and improved drive currents.

A Pattern Reconfigurable Antenna Using Eight-Dipole Configuration for Energy Harvesting Applications.

A pattern reconfigurable antenna, composed of eight elements, is proposed for energy harvesting applications. Pattern reconfigurable antennas are a promising technique for harvesting from different wireless sources. The radiation pattern of the proposed antenna can be steered electronically using an RF switch matrix, covering an angle range from 0 to 360 degrees with a step size of 45 degrees. The proposed antenna primarily consists of an eight-dipole configuration that shares the same excitation. Each dipole is excited using a balun comprising a quarter-wavelength grounded stub and a quarter-wavelength open-circuit stub. The proposed antenna operates in the frequency range of 4.17 to 4.5 GHz, with an impedance bandwidth of 7.6%. By switching between the different switches, the antenna can be steered with a narrower rotational angle. In addition, the antenna can work in an omnidirectional mode when all switches are in the ON state simultaneously. The results demonstrate a good agreement between the numerical and experimental findings for the reflection coefficient and radiation characteristics of the proposed reconfigurable antenna.

Quad Element MIMO Antenna for C, X, Ku, and Ka-Band Applications.

This article presents a quad-element MIMO antenna designed for multiband operation. The prototype of the design is fabricated and utilizes a vector network analyzer (VNA-AV3672D) to measure the S-parameters. The proposed antenna is capable of operating across three broad frequency bands: 3-15.5 GHz, encompassing the C band (4-8 GHz), X band (8-12.4 GHz), and a significant portion of the Ku band (12.4-15.5 GHz). Additionally, it covers two mm-wave bands, specifically 26.4-34.3 GHz and 36.1-48.9 GHz, which corresponds to 86% of the Ka-band (27-40 GHz). To enhance its performance, the design incorporates a partial ground plane and a top patch featuring a dual-sided reverse 3-stage stair and a straight stick symmetrically placed at the bottom. The introduction of a defected ground structure (DGS) on the ground plane serves to provide a wideband response. The DGS on the ground plane plays a crucial role in improving the electromagnetic interaction between the grounding surface and the top patch, contributing to the wideband characteristics of the antenna. The dimensions of the proposed MIMO antenna are 31.7 mm × 31.7 mm × 1.6 mm. Furthermore, the article delves into the assessment of various performance metrics related to antenna diversity, such as ECC, DG, TARC, MEG, CCL, and channel capacity, with corresponding values of 0.11, 8.87 dB, -6.6 dB, ±3 dB, 0.32 bits/sec/Hz, and 18.44 bits/sec/Hz, respectively. Additionally, the equivalent circuit analysis of the MIMO system is explored in the article. It's worth noting that the measured results exhibit a strong level of agreement with the simulated results, indicating the reliability of the proposed design. The MIMO antenna's ability to exhibit multiband response, good diversity performance, and consistent channel capacity across various frequency bands renders it highly suitable for integration into multi-band wireless devices. The developed MIMO system should be applicable on n77/n78/n79 5G NR (3.3-5 GHz); WLAN (4.9-5.725 GHz); Wi-Fi (5.15-5.85 GHz); LTE5537.5 (5.15-5.925 GHz); WiMAX (5.25-5.85 GHz); WLAN (5.725-5.875 GHz); long-distance radio telecommunication (4-8 GHz; C-band); satellite, radar, space communications and terrestrial broadband (8-12 GHz; X-band); and various satellite communications (27-40 GHz; Ka-band).

Semi-Coprime Array with Staggered Beam-Steering of Sub-Arrays.

A split-aperture array (SAA) is an array of sensors or antenna elements in which the array is split into two or more sub-arrays (SAs). Recently proposed SAAs, namely coprime and semi-coprime arrays, offer to attain a small half-power beamwidth (HPBW) with a small number of elements, compared to most conventional unified-aperture arrays, at the cost of reduced peak-to-side-lobe ratio (PSLR). To reduce HPBW and increase PSLR, non-uniform inter-element spacing and excitation amplitudes have proven helpful. However, all the existing arrays and beam-formers suffer increased HPBW, degraded PSLR or both when the main beam is steered away from the broadside. In this paper, we propose staggered beam-steering of SAs, a novel technique for decreasing HPBW. In this technique, we steer the main beams of the SAs of a semi-coprime array to angles slightly different from the desired steering angle. In conjunction with staggered beam-steering of SAs, we have utilized Chebyshev weights to suppress the side lobes. The results show that the beam-widening effect of Chebyshev weights can be mitigated considerably by staggered beam-steering of the SAs. Ultimately, the unified beam-pattern of the whole array offers HPBW and PSLR better than the existing SAAs, uniform and non-uniform linear arrays, especially when the desired steering angle is away from the broadside direction.

Four-Port 38 GHz MIMO Antenna with High Gain and Isolation for 5G Wireless Networks.

In this paper, a 38 GHz 4-port multiple-input multiple-output (MIMO) antenna with considerable isolation and gain enhancement for 5G applications is introduced. The suggested antenna element is a monopole antenna composed of a circular patch with a rectangular slot etched from it and a partial ground plane is used to extend the desired frequency to operate from 36.6 GHz to 39.5 GHz with a center frequency of 38 GHz. The high isolation is achieved by arranging the four elements orthogonally and adding four stubs to reduce mutual coupling between elements at the desired frequency bands. The gain improvement is also introduced by placing a frequency selective structure (FSS) which is designed at the same frequency bands of the antenna under the suggested MIMO antenna to act as a reflector. The proposed four-element MIMO with the FSS prototype is built and tested in order to confirm the simulated results. The suggested antenna operated from 37.2 GHz to 39.2 GHz with an isolation of less than 25 dB across the obtained frequency range. The peak gain of the antenna is enhanced from 5.5 dBi to around 10 dBi by utilizing the FSS structure; furthermore, the back radiation is enhanced. The MIMO performance is validated by extracting its parameters and comparing with the simulated results. The results extracted from the simulation and the measurement show satisfactory matching along with the target band, indicating that the proposed structure could be used for 5G communications.

A Frequency Reconfigurable Folded Antenna for Cognitive Radio Communication.

In this work, a spectrum-sensing monopole antenna was used to operate in different frequency bands for cognitive radio applications. The proposed antenna consists of a folded monopole antenna with a partial ground plane, and it can be used for various wireless technologies operated at various frequencies from 1.5 to 3.5 GHz. The suggested antenna was printed on a RO4003 substrate with 3.38 permittivity and an overall size of 60 × 60 × 0.813 mm3. To achieve reconfigurability of the antenna, PIN diodes (HPND-4005) were inserted at different lengths along the antenna to obtain the desired performance. The antenna was fabricated and experimentally tested to validate the simulation outcomes, and distinct consistency between the simulation and measurement outcomes was obtained. Computer simulation tool (CST) software was used to design and simulate the suggested antenna and then the model was fabricated to validate the simulation outcomes.

Miniature Mesa Extension for a Planar Submicron AlGaN/GaN HEMT Gate Formation.

In this letter, a novel approach is presented to overcome issues in AlGaN/GaN high electron mobility transistors (HEMTs), such as metal discontinuity of the gate stemmed from conventional mesa isolation. This usually requires a careful mesa etch process to procure an anisotropic mesa-wall profile. An alternative technique is the use of ion implantation for device isolation instead of conventional mesa for a planar device formation. However, ion implantation is a costly process and not always easily accessible. In this work, the proposed method is to simply extend the mesa below the gate just enough to accommodate the gatefeed, thereby ensuring the entire gate is planar in structure up to the gatefeed. The newly developed device exhibited no compromise to the DC (direct current) and RF (radio frequency) performance. Conversely, it produced a planar gate configuration with an enhanced DC transconductance (approximately 20% increase is observed) and a lower gate leakage while the etch process is considerably simplified. Similarly, the RF transconductance of proposed device (device B) increased by 80% leading to considerable improvements in RF performance.

Development and Modelling of Gallium Nitride Based Lateral Schottky Barrier Diodes with Anode Recesses for mmWave and THz Applications.

This paper presents novel multi-channel RF lateral Schottky-barrier diodes (SBDs) based on AlGaN/GaN on low resistivity (LR) (σ = 0.02 Q·cm) silicon substrates. The developed technology offers a reduction of 37% in onset voltage, VON (from 1.34 to 0.84 V), and 36% in ON-resistance, RON (1.52 to 0.97 to Ω·mm), as a result of lowering the Schottky barrier height, Φn, when compared to conventional lateral SBDs. No compromise in reverse-breakdown voltage or reverse-bias leakage current performance was observed as both multi-channel and conventional technologies exhibited a VBV of (VBV > 30 V) and an IR of (IR < 38 µA/mm), respectively. Furthermore, a precise small-signal equivalent circuit model was developed and verified for frequencies up to 110 GHz. The fabricated devices exhibited cut-off frequencies of up to 0.6 THz, demonstrating the potential use of lateral AlGaN/GaN SBDs on LR silicon for high-efficiency, high-frequency integrated circuits' applications. The paper begins with a brief outline of the basic Schottky-contact diode operation. A series resistance analysis of the diode studied in this project is discussed. The small signal equivalent circuit of the Schottky-contact diode is presented. The layout of the diodes studied is described, and their fabrication techniques are briefly mentioned. DC, RF, and low frequency C-V measurement techniques and measurements to characterize the diodes are outlined. Finally, results and discussions on the effects of multiple recesses under the Schottky-contact (anode) obtained from the I-V diode characteristics and C-V measurements, and the small signal equivalent circuit deduced from RF measurements for different diode configurations, are presented.