GHz Band Research Articles

Circular Shaped Ultrawide-Band Antenna for Wireless Communication

This paper presents the design of (UWB) antenna with asymmetrical U-Slot, operating in the microwave band of (3.5-15) GHz. This design permits its applications in various sectors, such as wireless communications, radar systems, and remote sensing. The antenna is covering bandwidth of (11.5) GHz with gain of (6.298) dB at (14.25) GHz. The substrate used is (FR4 Epoxy) of (????????=4.4), loss tangent of (0.02), and thickness of (1.575) mm. The extensive bandwidth of the antenna makes it operate in both the C-Band and X-Band. Overall, the design of this (UWB) antenna aims to provide a high-performance antenna that can operate over a wide frequency range, making it suitable for various applications.

Concept and Design of a Multi-Polarization Reconfigurable Microstrip Antenna with Symmetrical Biasing Control.

Wireless communication systems have grown rapidly, moving towards being highly compact, intelligent, and flexible to adapt to changing operating requirements. Multifunctional and highly versatile antennas are key in this development to ensure system quality. Reconfigurable antennas, particularly regarding polarization, allow frequency reuse and enable the mitigation of fading effects. This work presents a square microstrip patch antenna operating in the ISM 5.8 GHz band with reconfigurable polarization by controlling its feeding. This antenna has four different states through the application of a symmetrical DC voltage that controls an RF circuit with PIN diodes. As a result, the microstrip patch can operate with three different polarizations: linear polarization and both circular polarizations (right-handed and left-handed). The antenna was fabricated to validate the proposed concept. The good agreement between the measurement and the simulation results was possible to observe regarding its polarization behaviour, impedance adaptation and radiation pattern.

A compact circularly polarized dual port MIMO antenna with DGS and parasitic patch for modern wireless communication and IOT applications

Abstract The article proposes a broadband dual-port planar multiple-input-multiple-output (MIMO) antenna for the lower sub-6 GHz band (1.67 GHz to 3.15 GHz) applications. The simple structure of the MIMO antenna system consists of a semi-annular ring-shaped patch with a covering cap-like structure connected with two symmetrical L-shaped structures. A partial ground with a rectangular mesh-like structure at the center is designed and the same rectangular mesh has been added as the parasitic element with the driven patch to attain circular polarization and enhanced isolation. The miniaturized dimensions of the two-port MIMO antenna system are 0.28 λ 0 × 0.54 λ 0. The suggested two-port MIMO antenna offers a wider impedance bandwidth (IBW) of 61.41% around the versatile resonant frequency of 2.4 GHz. The proposed MIMO also depicts a minimum isolation of 26 dB with an edge-to-edge spacing of 0.19 λ 0. An axial ratio bandwidth of 280 MHz is attained between 2.36 GHz and 2.64 GHz. The proposed antenna shows good IBW with excellent isolation, along with good radiation and MIMO diversity characteristics to operate at 2.4 GHz with circular polarization. The designed MIMO antenna can be utilized for IoT and modern mobile wireless applications as the broad bandwidth covers various IoT communication protocol frequencies such as 1.8 GHz (NB-IoT) and 2.4 GHz (Wireless LAN).

Elliptical Multi Orbital Truncated Flexible Patch Antenna Using PDMS Substrate for Sub 6 GHz Applications

This paper presents an elliptical-shaped multi-orbital truncated patch antenna applicable forsub-6 GHz bands. The sub-6 GHz bands cover 5.8 GHz high-speed wireless communication. The antenna is designed on a Poly Dimethylsiloxane (PDMS) substrate. PDMS is used for designing the proposed antenna. It is a flexible substrate with a dielectric constant εr value of 2.7 and a loss tangent tan δ value of 0.022. The substrate dimension is 20×15×1.6 mm3in which a patch is created with the size of 12.5×13 mm2. The proposed antenna resonates at 6.2 GHz showing a reflection coefficient (s11) value of -37 dB. The impedance bandwidth of the antenna is 1.225 GHz in the range of 5.5-6.725 GHz frequency, and the maximum peak gain is about 3.5 dB. The proposed antenna is simulated, fabricated, and experimentally tested.

Dual-Band Millimeter-Wave MIMO Antennas For 5G Wireless Implementation

For 5G wireless applications, this exploration proposes a dual-band 28/38 GHz 4-component MIMO array depending on duplex-mode planar monopole antennas. Four planar monopole antennas are part of the layout framework, situated at the districts of a Rogers RO4003 substrate measuring 20 by 20 mm2 and with a dielectric constant of 3.55. The form of the suggested placoid monopole antenna is crescent-shaped. We created a notch at the bottom and inscribed two rectangular holes on each side to get the required behaviour and execution. For enhancement of isolation, we also employed a limited ground plane. Antenna elements can achieve significant isolation (> − 23 dB) using spatial and scattering behaviour approaches. A illustration of the four-element MIMO array is created, manufactured, and measured to multifariousness the outline idea. The investigational outcomes demonstrate that the suggested antenna has strong isolation and high efficiency while covering the 27.25–29 GHz and 34.5–41 GHz bands. Additionally, studies are done on the channel capacity, realized gain, and radiation pattern. The obtained findings suggest that, for millimeter-wave 5G MIMO implementation, the proposed MIMO antenna might be an excellent application-oriented design.

A dual‐wideband 5G antenna with dual polarization in the sub‐6 GHz band and 2 × 2 MIMO function in the 28‐GHz band

AbstractA novel aperture‐shared dual‐wideband 5G antenna with dual polarization in the sub‐6 GHz band and multi‐input multi‐output (MIMO) function in the 28‐GHz band is presented in this work. A dual‐polarized megnetoelectric dipole (ME‐dipole) with wide bandwidth is introduced in the sub‐6 GHz band. Based on the partial structure reuse method, four 2 × 2 substrate integrated waveguide (SIW) cavity‐backed patch arrays are integrated into the electric dipole structure of the ME‐dipole to construct a 28‐GHz 2 × 2 MIMO system. Two high‐order SIW cavity modes that cooperate with patch modes are used to enhance bandwidth in the 28‐GHz band. For demonstration, a prototype of the proposed antenna was fabricated and measured. The simulated results are in good agreement with the measured results, showing wide bandwidths of 39.6% and 10.85% in the sub‐6 GHz and the 28‐GHz bands, respectively. In addition, excellent measured in‐band and cross‐band isolations of over 44.4 dB and 45.2 dB are obtained, respectively.

Mutual coupling reduction between antennas array for 5G mobile applications

This paper introduces the design of a multiple-input-multiple-output (MIMO) antenna optimized for low-profile applications supporting sub-6 GHz fifth-generation (5G) wireless applications. We have started the design from a single antenna with a square patch shape, each antenna array is composed from 4-element radiators fed by using power dividers and quarter microstrip lines. Mounted on a single Rogers RT5880 substrate, the MIMO antenna functions at 3.5 GHz. In order to miniature and to decrease the mutual coupling between the both antennas array we have optimised a magnetic wall based on periodic structures permitting to decrease the mutual coupling between the both antenna array. The unit element from the wall was optimised, studied and validated in order to absorb the surface current and to enhance the isolation between the different radiating elements. The dimensions of the proposed MIMO antenna are 154×220×0.578 mm³. The MIMO antenna final circuit achieves a peak gain of 9 dBi and an isolation around -30 dB. The introduction of the magnetic wall permits to enhance the isolation between the antenna array from -20 dB to -30 dB at 3.5 GHz band. This advancement contributes to the overall performance improvement of the MIMO antenna system.

A Terahertz GaN solid‐state power amplifier on radial combining technique

AbstractTerahertz (THz) bands are considered to have various anticipated applications. Output power is an important factor determining the operating distance of THz systems, but it is very challenging to achieve high output power under current solid‐state terahertz circuit technology. The paper first presents a four‐way G‐band radial combiner, which features high passive efficiency of 88% and compact size. Moreover, based on this radial combiner and in‐house fabricated gallium nitride chips, a solid‐state power amplifier prototype is further demonstrated. Measured results show that, the average saturated output power is 21.7 dBm across the 180–240 GHz band with a typical output power of 23.2 dBm at 189 GHz.

Demonstration of THz frequency hopping in the 300 GHz band based on UTC-PD and tunable DFB laser array

We explored the potential of an optoelectronic frequency hopping system within the 300 GHz band, leveraging a tunable distributed feedback laser array and uni-traveling carrier photodiode. Our experiments successfully achieved a 10-channel terahertz (THz) frequency hopping, marking a significant advancement in THz secure communication technologies. Notably, the system exhibited a rapid frequency-hopping capability with a short transition time of 0.8 ms between channels, ranging from 288 to 331 GHz. Further, we conducted data transmission tests at a rate of 5 Gbit s−1 across several channels. The results were promising, showing each channel maintained a clear eye pattern and a low bit error rate, crucial factors for reliable and secure data transmission. These findings not only demonstrate the efficacy of our system but also open new avenues for high-speed, secure THz communication.

Channel Measurements and Modeling of Wooded Hilly Terrain At Sub-1 GHz Band

Channel Measurements and Modeling of Wooded Hilly Terrain At Sub-1 GHz Band

Non-volatile voltage-controlled magnetization in single-phase multiferroic ceramics at room temperature

Single-phase multiferroics (MFs) exhibiting ferroelectricity and ferromagnetism and the strong magnetoelectric (ME) coupling effect at room temperature are seen as key to the development of the next-generation of spintronic devices, multi-state memories, logic devices and sensors. Herein, the single-tetragonal phase (1–x) (Sr0·3Bi0·35Na0·329Li0.021)TiO3-xBiFeO3 (x = 0.2 or 0.4) system was designed to study the intrinsic ME coupling effect at room temperature and high frequencies. The polarization arises from the cooperative displacement of both Fe3+ and Ti4+ relative to the oxygen sublattice in the tetragonally distorted perovskite structure, and the magnetization stems from indirect exchange magnetic interaction between adjacent iron ions. A switchable voltage-controlled magnetization was confirmed by a change of the coercive magnetic field, Hc, and remnant magnetization, Mr, in the x = 0.4 component subjected to an external electric field at room temperature and was possibly attributed to a strain-mediated ME coupling effect. In addition, resonance behaviours of the complex magnetic permeability and complex dielectric permittivity in the GHz band indicate that this ME effect is intrinsic in nature and could broaden the applications of multiferroics to devices operating at microwave frequencies.

A Simultaneously Transmit and Receive Antenna Terminal for In-Band Full-Duplex Applications

In this paper, a low-profile co-linearly polarized simultaneously transmit-receive antenna (STRA) terminal is presented for 5G and upcoming technologies. The proposed STRA terminal comprises of an identical pair of spatially rotated half-circular microstrip antennas for transmission (Tx) and reception (Rx). The challenge of self-interference (SI) is addressed by employing passive SI cancellation techniques such as spatial diversity, field confinement, and surface perturbations. This has been accomplished by using fence-strip structure and V-shaped slots in the ground plane. The STRA was designed, fabricated, and tested for full-duplex operation in a sub-6 GHz band lying from 5.73 to 5.88 GHz, providing high interport isolation ranging from 35.5 dB to a maximum of 46.5 dB. The proposed STRA was implemented using Rogers 3003™ substrate. The measurements yield radiation characteristics with high gain of 5.45-6.0 dBi and 5-6.5 dBi for Tx and Rx antennas, respectively. The measured results are in good conformance with the simulated design. This antenna finds its potential usage in V2X and private 5G networks and can be extended for full-duplex MIMO implementations.

Slot fed circularly polarized magneto-electric dipole antenna array fed by optimized printed microstrip gap waveguide network

<p>A compact, circularly polarized 8 × 8 antenna array is designed for the 60 GHz band. The array comprises circularly polarized magneto-electric dipoles (CP-ME-Dipole) excited by narrow slots. The slots are fed by a printed gap waveguide (PGWG) cooperative network optimized based on the termination of the effective impedance of the array elements. Thus, it accounts for the space mutual coupling of the antenna elements. A procedure based on the full-wave analysis of a 4 ´ 4 array is used to estimate each element’s 8 × 8 array effective port impedance. The cooperative feeding network is designed based on the known effective impedances. The array is divided into two half subarrays out of phase from each other, and a rectangular waveguide feeds both sides. The commonly measured bandwidth of 18.3% achieves return loss better than 10 dB and an axial ratio below 3 dB (AR) of less than 3 dB. A maximum gain of 26.2 dBic with a high radiation efficiency of 82% radiation efficiency.</p>

A Dual-Band Low SAR Microstrip Patch Antenna with Jean Substrate for WBAN Applications

This paper presents a low-profile dual-band microstrip patch antenna operated at the 2.45/5.8 GHz ISM bands, targeting wireless body area network (WBAN) applications. The proposed antenna is fabricated on a jean substrate measuring 74×82 mm2. The four corners of the conventional rectangular patch are cut to activate an additional operating frequency and to enhance the radiation pattern. The circular slot is added to the radiating patch to fine-tune the desired frequencies. The measured impedance bandwidth of the proposed antenna at 2.45 GHz and 5.8 GHz bands is 3.68% (2.40 GHz–2.49 GHz) and 3.81% (5.67 GHz–5.89 GHz), respectively. The measured maximum gains are 3.08 dBi at 2.45 GHz and 2.15 dBi at 5.8 GHz. Moreover, the antenna’s performance when placed on flat and rounded body surfaces is also investigated. The proposed antenna achieves stable radiation pattern and low specific absorption rate (SAR) value with low complexity in design. The results indicate that the proposed antenna can be a promising candidate for WBAN applications.

Enhancing 5G propagation into vehicles and buildings using optically transparent and polarisation insensitive metasurfaces over wide-incidence angles

This article introduces two transmissive metasurfaces applied to normal windows, aiming to improve the 5G outdoor-to-indoor (O2I) coverage. These windows can be utilized in various settings, such as vehicles or buildings. The proposed unit cells, designed to be wide-incident angle and polarization insensitive, are implemented in both single-glazing and double-glazing glasses, arranged in a periodic structure to form the transmission surfaces. Both metasurfaces maintain optical transparency by incorporating Indium Tin Oxide (ITO) as the conductive element in each unit cell. These engineered transmission surfaces enhance the 5G signal indoor coverage at the 3.5 GHz band across a broad range of incident angles. While multi-layer structures typically exhibit heightened sensitivity to the angle of incidence, the proposed two-layered transmissive surfaces demonstrate substantial angular stability, reaching up to 65 and 75 degrees for double- and single-glazed glass, respectively. To achieve this wide and stable angular response, evolutionary optimization techniques were employed to fine-tune the proposed unit cells. Both designs exhibit a high transmission coefficient across the operating frequency for a variety of incident angles, surpassing those reported in the existing literature. Experimental evaluations of the fabricated prototypes indicate that both metasurfaces hold significant potential for enhancing signal propagation into buildings and vehicles.

Design optimization for microstrip antennas based on polymethyl methacrylate (PMMA) substrate and carbon nanotube (CNT) conductive material in sub-6 Ghz band

Abstract Background The rapid expansion of modern smart applications, demanding faster data transfer and extensive bandwidth, has prompted the development of new-generation networks like 5G and 6G. These networks encompass additional frequency bands such as sub-6 GHz, millimeter waves, and terahertz bands to meet the growing bandwidth requirements. However, despite the substantial bandwidth available in these bands, several challenges must be addressed to overcome unfavorable propagation characteristics. Moreover, numerous applications necessitate wireless devices with antennas that exhibit high flexibility and exceptional radiation responses, particularly when subjected to bending effects. This requirement highlights the importance of polymers-based antennas that can adapt to changing conditions while maintaining optimal performance. The present comprehensive study delves into the performance evaluation of rectangular and circular microstrip antennas utilizing PMMA (polymethyl methacrylate) polymer substrate with varying thicknesses. Results Notably, CNTs (Carbon Nanotubes) are employed as an alternative to traditional copper for the conductive part and ground plane. Both PMMA-based antennas, integrated with CNTs, exhibit a compact footprint of 27.8 × 47.8 × 1.5 mm3 for the circular antenna and 22.8 × 39.5 × 1.5 mm3 for the rectangular antenna. Impressively, the realized gain of both antennas surpasses 5 dBi, demonstrating robust performance in both flat and bending scenarios across different substrate thicknesses. Conclusions The rectangular antenna achieves a bandwidth of approximately 200 MHz, while the circular microstrip antenna showcase annotable bandwidth of 500 MHz. These exceptional outcomes position the two microstrip antennas as highly suitable for a diverse range of emerging applications within the sub-6 GHz band (the frequency range below 6 GHz in the radio spectrum). Thus, the combination of PMMA substrate, CNTs and the compact form factor of the antennas presents a compelling solution for meeting the demands of modern applications requiring efficient wireless communication with enhanced performance and bandwidth.

Depositing gradient thickness silver film on CNF/rGO/polyimide surface to form a sandwich structure for efficient electromagnetic interference shielding

Deployable satellites in space are exposed to high-frequency electromagnetic interference (EMI) for long periods of time, resulting in shortened lifetimes, so there is an urgent need for supportive electromagnetic shielding materials. To address this limitation, our team has developed innovative ultrathin carbon nanofiber/reduced graphene oxide/polyimide (CNF/rGO/PI) composites. It has excellent strength, shape memory properties, thermal stability and wide temperature range tolerance. Among them, polyimide with 4 % CNFs and 4 % rGO (CGPI44) has the best performance. Gradient-thick Ag films are deposited on both sides of the CGPI44 substrate by magnetron sputtering to form sandwich structure composites. With a sputtered Ag thickness of only about 5 μm and a total thickness of 0.146 mm, the material exhibited an extremely high electrical conductivity and excellent EMI shielding effectiveness (SE) of up to 112 dB in the 8.2–12.4 GHz band. Finite element analysis is performed to calculate the electric field strength and energy distribution. By providing a feasible scheme for highly effective shielding of high-frequency EMI, this approach will promote research on magnetron-sputtered polymer composites in the field of electromagnetic shielding.

An Innovative Conformal Electronically Scanned Array Antenna for full 360° Steerability in the Ka-band

A novel approach to constructing an omnidirectional 5G/6G Ka-band Tx/Rx frontend module using an Active Electronically Steerable Array (AESA) will be presented. The 5G standard includes a number of mmWave frequency bands that provide the bandwidth for high data rates. However, up to now 5G still transmits primarily in the sub-6 GHz frequency range. Small cells like micro or pico cells operated in the mmWave range are capable to increase network capacity in densely populated areas. Efficient beam-based communications using directional antenna arrays can overcome the limitations imposed by propagation loss at high frequencies. These and a number of further requirements have been taken into account in the design of the antenna module presented here, making it a fundamental component for the cellular infra— structure of future 5G/6G mmWave networks. The dualpolarised module is using 2 x 96 elements to scan 360° in azimuth and ±45° in elevation. The operation frequency range is 24.25 GHz to 29.5 GHz, covering n258, n257, and n261 3GPP bands. Additionally, the module is capable to control up to four beams simultaneously.

3D printed circularly polarized implantable antenna with wideband impedance matching

Abstract This article proposes a slot-loaded circularly polarized implantable antenna with wide bandwidth at 2.45 GHz, i.e., Industrial, Scientific, and Medical (ISM) band. This antenna is established with a compact size of 44.52 mm3 based on 3D printing technology, and biocompatible material MED610 is adopted for human safety consideration. During the design, unilaterally shorted patch antenna loaded with T-slot is adopted, obtaining two closely spaced orthogonal modes with miniaturized antenna size. More importantly, to obtain wide impedance matching, a spiral slot is introduced around the feed, forming an L-section network consisted of a parallel capacitor and a series inductor. As a result, a wide circular polarization bandwidth of 28.7 % is realized for the proposed antenna. The measured results are well agreed with simulated results.

Antipodal vivaldi array MIMO antenna for 5G FR2 applications at 28 GHz with improved isolation

Abstract This paper proposed a two port antipodal vivaldi antenna (AVA) for 5G FR2 (frequency range 2) applications at 28 GHz with improved bandwidth,gain and isolation. Each antenna consists of two array elements. The proposed antenna has dimensions 23.8 × 54 × 0.79 mm3 and is fabricated on Rogers RT/Duroid 5880 material. This material has a 2.2 low dielectric constant and mainly suitable for broadband high frequency applications. Proposed antenna covers −10 dB below from 25.51 to 33 GHz band, which having 7.49 GHz bandwidth. Gain for the presented MIMO (Multiple input multiple output) AVA array is varying from 8.50 to 12.44 dBi. A better isolation −34.56 dB is obtained between two antenna elements. MIMO characteristics like ECC (Envelope correlation coefficient), CCL (Channel capacity loss), DG (Diversity Gain), TARC (Total active reflection coefficient), and MEG (Mean effective gain) are satisfied with good results for presented antenna. The proposed antenna is designed using ansys HFSS simulation tool.