GHz Band Research Articles

Evaluation of interference between 300 GHz band fronthaul links using measured high gain antenna radiation patterns

Evaluation of interference between 300 GHz band fronthaul links using measured high gain antenna radiation patterns

SMALL-SCALE MIMO ANTENNA WITH HIGH ISOLATION FOR 5G COMMUNICATION

This manuscript describes two- and three-element small-scale multiple-input multiple-output (MIMO) antenna configurations for 5G communications ranging from 23.5 to 28.6 GHz. Modern device antennas have two essential features: isolation and a larger bandwidth. In this regard, firstly a single element antenna has been designed using quarter wavelength impedance transformer and semi-circular loaded patch along with defected ground structure. Furthermore, two single-element antennas are placed orthonormal to each other having quarter wavelength distance from the center of the single-element antenna. To increase the bandwidth and isolation, additionally a rectangular patch and strip isolate from ground. This structural change alters the current path, improving the impedance matching and isolation of the two-element MIMO antenna configuration. After that the three-element MIMO configuration was formed by placing two single-element antennas orthogonally at quarter wavelength from the center of the single-element antenna. The total size of two- and three-element MIMO antenna is 15 × 11 × 1.6 mm and 20 × 11 × 1.6 mm, respectively. The proposed MIMO antennas provide isolation of more than 21 dB and gain more than 25 dB throughout the working band. MIMO diversity features function reasonably well, with an envelope correlation coefficient of less than 0.002 and diversity gain of 10. Proposed antennas can be a good candidate for MIMO applications in the 5G communication frequency range 2 (FR2), 28 GHz bands.

Demonstration of 120 Gbit/s 64-QAM Wireless Link Operating in the 300 GHz Band

Demonstration of 120 Gbit/s 64-QAM Wireless Link Operating in the 300 GHz Band

Doppler velocity decomposition based radar imaging by 79 GHz band millimeter wave radar

Doppler velocity decomposition based radar imaging by 79 GHz band millimeter wave radar

Novel Design of X-Shaped Slot Antenna Backed by a Flat Reflector for 5G Sub-6 GHz Band

Novel Design of X-Shaped Slot Antenna Backed by a Flat Reflector for 5G Sub-6 GHz Band

A Low-Profile, Wide-Angle, and Bandwidth Enhanced Rectenna for Radiative Energy Harvesting in the 12 GHz Band

A Low-Profile, Wide-Angle, and Bandwidth Enhanced Rectenna for Radiative Energy Harvesting in the 12 GHz Band

Broadband Waveguide-to-Differential-Line Transition in Multi-Layer Substrates With Triple Stacked Patch in 300 GHz Band

Broadband Waveguide-to-Differential-Line Transition in Multi-Layer Substrates With Triple Stacked Patch in 300 GHz Band

Design and Performance Analysis of Defected Ground Slotted Patch Antenna for Sub-6 GHz 5G Applications

Recently, there have been notable advancements in wireless communication systems to address the deficiencies of fourth generation (4G) wireless technology, such as insufficient spectrum bandwidth, slow data transfer rates, and constrained network capacity. These issues may be addressed in fifth generation (5G) wireless technology, which is no longer stand-alone. This article proposes and designs a defected ground slotted patch antenna (DGSPA) for 5G (Sub-6 GHz band) applications. It can work at 3.5 GHz in the 5G N77 band, Sub-6 GHz 5G, LTE Band 42, and WiMAX. The suggested antenna has an overall dimension of 38×38×1.575 mm3 and is built on the Rogers RT5880 substrate material, whose dielectric permittivity is 2.2. The CST software is used as the simulation tool to analyze the designed antenna’s performance. The novelty of the recommended antenna is in terms of its small size with defective ground structure (DGS), high antenna gain, perfect impedance matching, and improved impedance bandwidth. The role of the DGS is evaluated by comparing the antenna’s performance with and without the DGS. It has been noticed that the DGS-backed antenna had an impedance bandwidth improvement of more than 11MHz, whereas the impedance profile is (50.086−????0.179) Ω, which denotes 50 Ω pure resistivity. It will operate within the frequency range of (3.4828 - 3.522) GHz with an impedance bandwidth of 69.2 MHz. The proposed antenna’s reflection coefficient (|????1,1|) is obtained as -54.028 dB at the resonating frequency of 3.5176 GHz, whereas the radiation gain and efficiency are observed as 6.463 dB and 93.475%, respectively. Thus, due to its promising performance based on radiation pattern, optimum efficiency, and higher bandwidth, the recommended defected ground slotted patch antenna can efficiently be used for the application of Sub-6 GHz 5G services.

Simulation based Comparative Review on a Metasurface based Perfect Absorber

In this paper, the different research papers are studied and comparatively analyzed to carry out the simulation based survey of various proposals for improvement to design Metarsurface based Perfect Absorber for GHz and THz frequency band for RF Energy Harvesting applications. Using a structure that can effectively absorb the most radiation is one of the biggest obstacles in reducing the impact of EM wave radiation. A perfect absorber may be created using variety of structures and materials with various specifications. Various structures are designed and simulated by different authors in variety of simulation softwares using useful parameters. Three distinct structures have been created, two of which were created using CST Microwave Studio and the third using HFFS for comparative study. A perfect absorber can be constructed for GHz and THz for dual band and multiband since the operating frequency range and band are not limited.

Asymmetric Coplanar Strip- (ACS-) Fed Side Edge Panel MIMO Antenna for IoT and 5G Applications

For future wireless high-speed wireless applications, the antenna design plays an indispensable role. Electrical compactness has been challenging over the years among the research fraternity. Hence, this paper proposes an electrically compact and miniaturized asymmetric coplanar strip- (ACS-) fed MIMO to bridge this research gap. In MIMO antennas, two electrically small antennas are used and are placed on the edges of the smartphone. A ladder-shaped radiator with a C-shaped slit inserted on the ground plane makes up the antenna’s monopole radiator. A compact antenna is proposed in this paper with dimensions of 0.076 λ×0.409 λ×0.005 λ. This achieves dual band characteristics, which cater to 3.5/5.5 GHz (WiMAX), 5.8 GHz (WLAN), 6.3 GHz (C-band), and sub-6 GHz 5G bands. For the available aperture, reasonable gain is attained by the proposed architecture. Furthermore, fractional bandwidth of 69% and 43% in 2.6 GHz and 5.5 GHz bands, respectively, acting in accordance with the bandwidth stated by Wheeler and Chu’s limit, has been attained in this ACS-fed antenna. In both the operating frequency bands, more than 20 dB isolation between the antenna elements has been achieved. High integrity is attained by the radiation pattern, and actual deployment is granted. Moreover, the simulated results presented are in good accordance with the measured results.

Modeling aperiodic sampling to increase the signal processing bandwidth of the sampling analog optical path

The paper discusses methods of aperiodic optical pulsed signal sampling in photonic analog-digital systems. We describe numerical modeling of aperiodic sampling and a method for reconstructing a spectrally sparse signal from aperiodicly selected samples. The described method is based on minimizing the l1 norm of the spectral representation of the reconstructed signal. Numerical simulations show that using aperiodic sampling, it is possible to reconstruct a spectrally sparse signal in the 5 GHz band using a sampling rate of 500 MS/s. The work also shows that using window functions it is possible to improve the quality of signal reconstruction from pseudo-random samples.

Area Efficient and Linear MMIC Based Ka Band Power Amplifier for 5G Communication Systems

This work presents a monolithic microwave integrated circuit (MMIC) based power amplifier (PA) with single 150 nm GaN high electron mobility transistor (HEMT) using broadband matching. For the proposed amplifier, two stage L-type biasing network is designed. In order to provide good linearity, low Q, broader bandwidth and optimized chip area, band pass filter (BPF) type matching network is proposed. The topology and parameter selection is done by performing proper load pull analysis. This helps in achieving wide band matching to maintain low Q factor. Thus the proposed amplifier is evaluated with post layout EM simulation data. For the 26 GHz band of 5G communication, proposed amplifier has a small signal gain of 11 dB for 21-27.4 GHz. The amplifier offers 33.42 dBm saturated output power and good linearity. The designed PA provides 31.35 dBm output power, 26% power added efficiency (PAE) and 29% drain efficiency (DE) at 1 dB compression with IP3 of 39.67 dBm for 26 GHz band. The designed PA has less complexity and small chip area of 4.3 mm2.

Application of switchable 4G/5G dual antenna system for laptops

AbstractThis work investigates a switchable 4G/5G dual‐antenna system designed for laptops. The dual open‐slot antenna structure is straightforward, with a slot width of only 2 mm. Each individual antenna features two different feed sections located in two separate regions between the slots. Port 1 is a direct‐feeding design with 3.6 pF chip capacitance, while Port 2 is only a direct‐feeding design. When Port 1 is excited and Port 2 is terminated to 50‐Ω, the antenna is functional in long‐term evolution (LTE) low‐band (617–960 MHz) and 5G sub‐6 GHz band (3300–5000 MHz). On the other hand, when Port 2 is excited and Port 1 is terminated to 50‐Ω, the antenna is functional in the LTE medium/high bands between 1710 and 2690 MHz. The measured isolation consistently exceeded 30 dB, and the efficiency remained above 48% across the entire frequency range. The calculated envelope correlation coefficients derived from the complex E‐field radiation pattern measurements were consistently below 0.02. These findings indicate that the system is exceptionally well‐suited for applications characterised by integrated metallic environments and a high display‐to‐body ratio.

A simple and modular quasi stepped impedance resonator based reconfigurable bandpass filter for 5G applications

A small-sized quasi-stepped impedance resonator (SIR) based single-band to dual-band reconfigurable bandpass filter is presented in this work. The proposed quasi-SIR filter is modular in nature and can be easily scaled to higher- or lower-frequency bands. To this end, a single- to dual-band reconfigurable modified SIR is designed. The designed reconfigurable resonator was then used to develop a single-band to dual-band reconfigurable filter. The proposed filter structure comprises two resonators loaded with PIN diodes to provide the switching. The filter allows switching between single and dual-band frequencies. In the OFF state, PIN diodes provide single-band resonance with a resonant frequency of 3.8 GHz. While the ON state of PIN diodes provides dual-band resonance of 3.35 GHz and 4.3 GHz. The structure of the filter is modular and is designed, analysed, and fabricated on a low-cost FR4 dielectric substrate with a 4.3 dielectric constant and 0.78 mm thickness. The measured results are in good agreement with the simulation results. The filter is designed to operate in the sub-6 GHz band, a designated band for 5G communication, and is thus suitable for incorporation in 5G devices with reconfigurability applications.

Fabrication of porous X-shaped Fe3O4@C core-shell structures for tunable microwave absorption

Designing porous materials with low density and high specific surface area is one of the strategies to obtain excellent wave absorbing properties. In this study, the carbon-coated porous X-shaped Fe3O4 composites used as microwave absorption materials were prepared by heat treatment of FeOOH@Polydopamine (PDA) core-shell precursors. It revealed that the X-shaped Fe3O4 core showed improved magnetic loss in GHz band due to its special shape anisotropy and large specific surface area. In addition, the modification of carbon enabled the Fe3O4 absorbers to have stronger polarization and higher electrical conductivity. The composites exhibited great freedom in performance tunability, allowing for strong absorption (RL<−40 dB) at different frequencies. For composites with thick carbon shell, the reflection loss reached the optimal value of − 64.92 dB at 15.04 GHz at the thickness of 1.75 mm, and the effective bandwidth was up to 4.64 GHz (13.04–17.68 GHz). The impressive performance of the as-prepared Fe3O4 @C core-shell composites was mainly attributed to the complementary behaviors of strong dielectric loss and magnetic loss.

Enhancing high-speed networks using RGB-based WLAN through Ro-FSO integration in the 5 GHz band

Abstract The limited bandwidth constraints imposed by conventional wireless carriers pose a significant hurdle when it comes to the delivery of high-speed broadband services. In response to this challenge, Radio over Free Space Optics (Ro-FSO) has emerged as a viable and innovative solution, seamlessly amalgamating wireless and optical systems. This integration proves particularly invaluable in sensitive environments, such as hospitals, where the risk of electromagnetic interference disrupting critical medical equipment is a real concern. Ro-FSO offers a disruption-free avenue for high-speed data transmission, positioning it as the ideal choice for broadband services, including Wireless Local Area Networks (WLANs). Within the scope of this study, we introduce a high-speed Ro-FSO link, showcasing the capability to concurrently transmit three independent channels with Red, Green and Blue (RGB) laser respectively, each supporting a robust 1 Gbps data rate. These data streams are skilfully up-converted to the 5 GHz RF bands, encompassing transmission distances of 650 m across the FSO channel. Our numerical simulation findings underscore the successful transmission of all the channels using wavelength division multiplexing (WDM), seamlessly meeting the prescribed Bit Error Rate (BER) and eye pattern criteria, solidifying the Ro-FSO’s standing as a promising solution for high-speed broadband delivery.

A Miniature Eight-Port Antenna Array Based on Split-Ring Resonators for 5G Sub-6 GHz Handset Applications.

In this article, a miniature eight-port multiple-input multiple-output (MIMO) antenna array is proposed for fifth-generation (5G) sub-6 GHz handset applications. The individual antenna element comprises a radiator shaped like the Chinese character "" (phonetically represented as "Wang") and three split-ring resonators (SRR) on the metal frame. The size of the individual antenna element is only 6.8 × 7 × 1 mm3 (47.6 mm3). The proposed antenna element has a -10 dB impedance bandwidth of 1.7 GHz (from 3.3 GHz to 5 GHz) that can cover 5G New Radio (NR) sub-6 GHz bands N77 (3.3-4.2 GHz), N78 (3.3-3.8 GHz), and N79 (4.4-5 GHz). The evolution design, the current distribution, the effects of single-handed holding, and the analysis of the parameters are deduced to study the approach used to design the featured antenna. The measured total efficiencies are from 40% to 80%, the isolation is better than 12 dB, the calculated envelope correlation coefficient (ECC) is less than 0.12, and the calculated channel capacity (CC) ranges from 35 to 38 bps/Hz. The presented antenna array is a good alternative to 5G mobile handsets with wideband operation, a metal frame, and minimized spacing.

Thinned Smart Antenna of a Semi-circular Dipole Array for Massive MIMO Systems

Massive MIMO (multiple-input multiple-output) is a multi-user MIMO technology that can provide high-speed multimedia services in 5G wireless networks using sub-6 GHz and millimeter wave bands. The massive MIMO (MMIMO) installs array antennas in the base stations, using hundreds of transceivers with other RF modules. One of the drawbacks of the MMIMO system is its huge power consumption, and the beamforming network with RF modules for a large number of antennas is the main contributor to the power consumption. In this paper, a novel beamforming method is proposed for the low power consumption of an MMIMO system. The proposed thinned smart antenna (TSA) of a semi-circular array produces a secure beam toward the user’s terminal with reduced interference. By thinning the antenna array, some of the antenna elements are kept off, resulting in less power consumption, while the array pattern remains the same as a fully populated array with a reduced side lobe level (SLL). The sub-6 GHz band of 5 GHz is used for the design of thinned array antennas. The genetic algorithm (GA) is used to determine the array sequence in thinning, and the adaptive signal processing algorithms least mean square (LMS), recursive least square (RLS), and sample matrix inversion (SMI) are used for the beamforming of the TSA, and the corresponding algorithms are GA-LMS, GA-RLS, and GA-SMI. The power saving of 40% to 55% is achieved using TSA. The maximum SLL reductions of 13 dB, 12 dB, and 14 dB are achieved for TSA using GA-LMS, GA-RLS, and GA-SMI algorithms, respectively.

Design of a Compact Microstrip Filtenna for Miniaturized Devices to Access Internet of Things Using Long Term Evolution

A filtenna or filtering antenna has both radiation and filtering functions and is an important module for the RF front-end of wireless devices. The main function of a filtering antenna is to filter out the out-of-band interferences from the adjacent bands. In this paper, the design of a compact coplanar microstrip filtering antenna at 2.6GHz band is presented. The antenna is designed for the miniaturized devices for the city connectivity to access the internet of things (IoT) services over 2.6GHz long term evolution (LTE) gateways. Filtering antenna is designed using hairpin bandpass filter integrated with semi-circular microstrip antenna. Filtering antenna is designed by computer simulation technology (CST) software and measurements are performed by vector network analyzer. Good impedance matching at 2.6GHz band is obtained for the filtering antenna by choosing appropriate dimensions of the hairpin bandpass filter. The simulated 10dB return loss bandwidth of filtering antenna is 4.65% with maximum gain of 1.9dB. Measured and simulated results agree well for the semi-circular filtenna.

Study on Improvement of Radio Propagation Characteristics of Cast Iron Boxes for Water Smart Meters.

Water utilities in Japan face a number of challenges, including declining water demand due to a shrinking population, shrinking workforce, and aging water supply facilities. Widespread use of smart water meters is crucial for solving these problems. The widespread use of smart water meters is expected to bring many benefits such as reduced labor by automating meter reading, early identification of leaks, and visualization of pipeline data to strengthen the infrastructure of water services, business continuity, and customer service, as detailed data can be obtained using wireless communication. Demonstration tests are actively conducted in Japan; however, many problems have been reported with cast iron meter boxes blocking radio waves. To address the issue, a low-cost slit structure for cast iron meter boxes is investigated in this study. The results confirm that the L-shaped tapered slit array structure with a cavity, which can be fabricated in a cast iron integral structure, satisfies the design loads required for road installation. The proposed slit structure achieved gain characteristics from -3.32 to more than 9.54 dBi in the 800 to 920 MHz band. The gain characteristics of conventional cast iron meter boxes range from -15 to -20 dBi, and the gain has been significantly improved. Antennas with a gain of -2.0 to +1.5 dB (0.8 to 2.5 GHz) were used for the transmitter antenna, which was found to have a higher gain than the transmit antenna in the 800 to 880 MHz frequency band. In the 1.5 to 2.0 GHz band, a high peak gain of 4.25 dBi was achieved at 1660 MHz, with no null and the lowest gain confirmed that this is an improvement of more than 10 dBi over conventional products.