Antenna Switching Research Articles

Enhanced reinforcement learning-based two-way transmit-receive directional antennas neighbor discovery in wireless ad hoc networks

The utilization of directional antennas for neighbor discovery in wireless ad hoc networks brings notable benefits, such as extended transmission range, reduced transmission interference, and enhanced antenna gain. However, when nodes use directional antennas for neighbor discovery, the communication range is limited, resulting in a lack of knowledge of potential neighbors. Hence, it is necessary to design a special antenna direction switching strategy for neighbor discovery based on directional antennas. Traditional methods of switching antenna directions are often random or follow predefined sequences, overlooking the historical knowledge of sector exploration for antenna directions. In contrast, existing machine learning approaches aim to leverage observed historical knowledge to adjust antenna directions for faster neighbor discovery. Nonetheless, the latency of neighbor discovery is still high because the node cannot fully utilize the observed historical knowledge (i.e., only using the knowledge observed by the node in transmission mode, ignoring the knowledge observed by the node in reception mode). Meanwhile, the corresponding reward and penalty mechanisms are still not detailed enough (i.e., these reward and penalty mechanisms only consider the sectors of discovered and undiscovered neighboring nodes, ignoring the scenario of sectors that have been rewarded). In this paper, the neighbor discovery process is modeled as a reinforcement learning-based learning automaton. We propose an enhanced reinforcement learning-based two-way transmit-receive directional antennas neighbor discovery algorithm, called ERTTND. The algorithm consists of a two-way transmit-receive reinforcement learning mechanism (TTRL) and an enhanced reward-and-penalty mechanism (ERAP). This algorithm leverages insights from nodes in transmission and reception modes to refine their tactical decisions. Then, through an enriched reward-and-penalty framework, nodes optimize their strategies, thus expediting neighbor discovery based on directional antennas in wireless ad hoc networks. Simulation results demonstrate that compared to existing representative algorithms, the proposed ERTTND algorithm can achieve over 30% savings in terms of average discovery delay and energy consumption.

Monolithic MIPI SOI CMOS single-pole fourteen-throw antenna switch module with on-chip transmit filters for cellular handsets

Monolithic MIPI SOI CMOS single-pole fourteen-throw antenna switch module with on-chip transmit filters for cellular handsets

Design of an Integrated Switching Antenna for Shielding Effectiveness Testing of Small Enclosures From 1 MHz to 100 MHz

Design of an Integrated Switching Antenna for Shielding Effectiveness Testing of Small Enclosures From 1 MHz to 100 MHz

Research on Development 3D Ground Penetrating Radar Acquisition and Control Technology for Road Underground Diseases with Dual-Band Antenna Arrays.

This paper describes the development of a new 3D ground-penetrating radar (GPR) acquisition and control technology for road underground diseases with dual-band antenna arrays. The 3D GPR system can be mounted on a vehicle-loading device and used by vehicles to detect road underground diseases at regular speeds. Compared with existing 3D GPR systems, this new type of 3D GPR has the following design features: it has dual-band antenna arrays, including a 16-channel 400 MHz antenna array and an 8-channel 200 MHz antenna array, which not only improves the detection efficiency, but also effectively balances the detection depth and detection resolution. A novel antenna switching method for time division step multiplexing (TDSM) is realized via field programmable gate array (FPGA), which not only avoids the crosstalk of antenna echo signals of different frequencies, but also ensures the interval of the same antenna working time. By combining the advantages of the FPGA and micro-control unit (MCU), and utilizing the high-speed transmission of the network port, the high-speed real-time transmission of the 3D GPR echo data is achieved. Finally, the integration of all software and hardware verified the correctness of the system, with good results.

Joint antenna selection and beamforming for frequency diverse multiple‐input multiple‐output radar in mainlobe spectrum interferences and signal‐dependent interferences coexistence scenarios

AbstractDue to the controllable degrees of freedom of frequency diverse array in the distance dimension, the frequency diverse multiple‐input multiple‐output (FDA‐MIMO) radar can easily deal with mainlobe interference, which is often difficult to solve in traditional phased arrays. Nevertheless, the performance of FDA‐MIMO radar will suffer from degradation in the scenario where spectrum interferences and signal‐dependent interferences coexist. In order to solve this problem, a novel FDA‐MIMO radar framework via antenna switching is proposed. Based on this framework, an effective method for jointly optimising antenna selection and beamforming against spectrum interferences and signal‐dependent interferences is developed. The resulting optimization problem is nonconvex and NP‐hard owing to the integer constraints caused by antenna selection. By relaxing the integer constraints, the original problem can be transformed into a convex optimization form and an iterative reweighting strategy is used to force the obtained solution to satisfy the integer constraints. Simulation examples show that the proposed algorithm has better performance in output signal‐to‐interference‐plus‐noise ratio (SINR) and beampattern radiation performance than the existing competitive methods.

A dual‐band polarization switchable antenna switch module for 5G new‐radio applications

SummaryIn this paper, a dual‐band antenna switch module with switching capability targeting the inter‐band carrier aggregation at 5G new‐radio (NR) frequency range 2 (FR2) is presented. Inter‐band carrier aggregation has become increasingly prevalent in millimeter‐wave applications at Ka‐band frequencies as a means to secure sufficient bandwidth for improving the rate of data transmission. Antenna modules with polarization switching capability are considered as a critical component for maintaining proper transmission and reception of the signals at millimeter‐wave frequencies. The integrated system consists of a wideband single‐pole‐double‐throw (SPDT) switch and a dual‐band power amplifier (PA) that are realized on the Rogers RO3010 substrate. With the two double exponentially tapered slot antennas (DETSA) arranged in the mutually orthogonal configuration, the antenna switch module can provide linear polarization at ±45 degrees. A measured error‐vector‐magnitude (EVM) of −30.3 dB at 38 GHz using 200‐MHz standard 5G NR 256‐QAM orthogonal frequency‐division multiplexing (OFDM) modulation has demonstrated the feasibility of the proposed module to be implemented for millimeter‐wave applications.

A Low-Cost Multibeam Switching Antenna Using Reconfigurable Hybrid Metasurface for Beamforming Applications.

In this paper, we proposed a multibeam switching antenna based on a low-cost reconfigurable hybrid metasurface applied for beamforming systems. The antenna consists of two parts: a microstrip feed antenna and a transmission hybrid metasurface. The latter is composed of three types of units with different amplitude and phase responses to electromagnetic waves so as to control the beams of the feed antenna. Sixteen PIN diodes are arranged in the metasurface with a simple bias network. When two different direct-current voltages are applied to the PIN diodes, the antenna can dynamically switch between two beams and four beams. For demonstration, the proposed antenna is fabricated, and the measured results show that the antenna operates at 9.07-9.42 GHz (-10 dB bandwidth) with a total size of 1.80λ0 × 1.52λ0 × 0.22λ0 (λ0 corresponds to the wavelength of 9.28 GHz in free space). With the merits of a compact structure, low cost and good radiation performance, the proposed design is suitable for beamforming applications.

A Sub-GHz CMOS SPDT Antenna Switch Employing Linearity-Enhanced Biasing Strategy for Second-Order Harmonic Reduction

A CMOS single-pole double-throw (SPDT) antenna switch employing linearity-enhanced biasing strategy is proposed for the second-order harmonic (H2) reduction. It was implemented and demonstrated using a 0.28-lm thick-oxide MOSFET in 65-nm CMOS process. The NMOS transistor of the conventional antenna switch is replaced with the CMOS transistor composed of an NMOS and PMOS transistor in parallel to improve second-order harmonic distortion (HD2). The optimum channel width of an NMOS and PMOS transistor is chosen to achieve odd symmetry characteristic of I-V curve with respect to the drain-to-source voltage swing (VDS), and, as a result, enhance HD2 of the antenna switch. In addition, the linearity-enhanced biasing scheme is adopted to the PMOS transistor as a conventional negative biasing method of the NMOS transistor. This prevents the degradation of the power handling capability in adopting the PMOS transistor to the antenna switch. In the measurement, the proposed single-stack SPDT antenna switch shows an insertion loss of less than 0.6 dB and an isolation of greater than 38 dB from 100 MHz to 1 GHz with an input and output return loss of greater than 25 dB. Concerning for H2 and third-order harmonic (H3), it shows H2 of -65 dBm and H3 of -90 dBm at 150 MHz when a single-tone RF signal with a power of +5 dBm is applied. Compared to the conventional NMOS-based antenna switch, the proposed CMOS-based antenna switch improves HD2 by approximately 8 dB, 7 dB, and 1 dB at 150 MHz, 400 MHz, and 1 GHz, respectively, while maintaining the comparable insertion loss, isolation, and third-order harmonic distortion (HD3).

An Improved AoA Estimation Algorithm for BLE System in the Presence of Phase Noise

Location-based service (LBS) provides users with personalized experience. With the latest Bluetooth low energy (BLE) technology, switched antenna array and constant tone extension (CTE) are introduced enabling angle of arrival (AoA) estimation for improved positioning accuracy. However, phase noise may significantly degrade the AoA estimation performance. Such impairment and its mitigation method are not well discussed in existing literature. In this paper, we theoretically analyze the performance degradation of AoA estimation caused by phase noise in BLE system. Based on the specific antenna switching pattern, an improved multiple signal classification (MUSIC) algorithm is proposed. We further propose an expectation maximization MUSIC (EM-MUSIC) algorithm to improve the AoA estimation accuracy by estimating the phase noise with extended Kalman filter. Simulation results show that at typical SNR level, the proposed algorithm can reduce the estimation error by more than 55% compared with existing algorithms. The proposed EM-MUSIC algorithm can greatly improve the positioning accuracy and is ideal for LBS.

A 1 mm ×1 mm CGM System on Die Achieving 1.65-nA/mM In Vivo Resolution and 0–40-mM/L Detection Range With ΔΣ Backscatter Technique

Diabetes has become a leading cause of death and disability all over the world. Continuous glucose monitoring (CGM) based on wireless power transfer (WPT) and backscatter communication enables wireless real-time telemetry to control glycemic levels in a long term. However, conventional backscatter techniques in CGM systems converted the sensing current into a bit stream or a frequency signal to switch the antenna, leading to two drawbacks: 1) Large power-harvesting antennas are required to complement the power loss in data converting and antenna switching and 2) Both the resolution and detection range are limited even with a high-performance glucose sensor. In this work, we propose a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta\Sigma$</tex-math> </inline-formula> backscatter technique to demonstrate a system on die (SoD) within a 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 1-mm on-chip antenna. Implemented in the 65-nm CMOS process, the proposed SoD achieves a telemetry error less than 0.25% with little impact on WPT, as well as a wide detection range of 0–40 mM/L. In vivo experimental results show that the CGM SoD realizes a resolution of 1.65 nA/mM.

A compact frequency reconfigurable beam switching antenna based on a single‐layer FSS

AbstractA compact frequency reconfigurable beam switching antenna based on a single‐layer frequency selective face (FSS) is proposed in this paper. The proposed antenna consists of a dual‐band dipole antenna and a single‐layer FSS with hexagonally arrangement. The omnidirectional radiation pattern of the dipole antenna designed as a radiation source and surrounded by the FSS can be converted into directional radiation pattern sweeping along the entire azimuthal plane at two single frequency of 2.4 or 5 GHz. The frequency selection is achieved by controlling the diode state of the FSS unit, and the beam switching is realised by a specific combination of electromagnetic wave reflection or transmission from the hexagonal FSS. The novelty lies in applying the hexagonal arrangement to a dual single‐frequency single‐layer FSS unit. This will not destroy the reflection or transmission characteristics of the FSS unit, but also contribute to reduce the antenna size and achieve a low cost. To validate the design, a prototype is fabricated and measured. The single‐layer FSS antenna with a volume of 57 mm × 57 mm × 58.5 mm can be scanned in 12 steps along the azimuth plane at 2.4 and 5 GHz, respectively.

A 28-GHz Four-Channel Beamforming Front-End IC With Dual-Vector Variable Gain Phase Shifters for 64-Element Phased Array Antenna Module

A 28-GHz fully differential four-channel beamforming front-end IC with variable gain phase shifters (VGPSs) is presented, of which orthogonal phase and gain control is achieved in a single block using the proposed dual-vector synthesis technique. This greatly reduces chip size, power consumption, and calibration complexity. The antenna switch embedded in the front-end matching network minimizes degradation of the transmitter (TX) efficiency and receiver (RX) noise figure. The multi-mode power amplifier (PA) with a built-in linearizer is presented to have high efficiency and linearity for all power modes, which reduces power consumption during gain control. Also, a differential four-way power divider and an single pole double throw (SPDT) switch are introduced in the common path, which has a small chip size and a low insertion loss. By adopting differential structures for all components in the four-channel IC, the effect of parasitic grounding inductances due to bonding and package is minimized. Thanks to the proposed dual-vector VGPS, the rms gain error of 0.21 dB and the peak phase variation of ±1.7° are achieved during phase control and gain control, respectively, without any calibration. The four-channel front-end IC also achieves rms phase error of only 1.4° during the simultaneous phase and gain control without any calibration. It has a TX OP1dB of 13.3 dBm and the highest linear output power of 7.2 dBm with 400-MHz 64-QAM fifth-generation (5G) new radio (NR) signals with 9.6-dB peak-to-average power ratio (PAPR). Also, this article presents a 64-element brick-type phased array antenna using four-channel core chips. It shows a high effective isotropic radiated power (EIRP) of 54.4 dBm at 28 GHz. An over-the-air link is demonstrated with a competitive data rate of 4 Gb/s using 64-QAM waveforms over all scan angles at a distance of 100 m.

A Multifrequency Seamless Dual-Link Handover Scheme Based on Beamforming for High-Speed Railway

This paper proposes a multifrequency seamless dual-link handover scheme based on beamforming for the high-speed railway (HSR) communication, i.e., when the train travels to the edge of overlapping area of the adjacent two cells, a gain beam is assigned to the overlapping area by the target base station (BS) using a beamforming technique to cover the entire region to enhance the received signal strength (RSS) and handover opportunity. The switching antenna is allowed to handover multiple times to improve the traditional scheme and reduce the handover failure probability (HFP) greatly. In the process of signal reception, considering the impact of the intercell cochannel interference on the RSS, the proposed scheme uses signal to interference ratio (SIR) instead of the RSS to indicate the received signal quality to optimize handover mode. The handover success probability (HSP) is analyzed to describe the relationship between train location and the probability. We also establish a probabilistic model and corresponding handover algorithm for the proposed scheme to complete the handover operations and theoretically analyze a series of indexes including handover trigger probability (HTP), HFP, communication interruption probability (CIP), and HSP. Theoretical and experimental results show that the proposed scheme can effectively improve the HTP and HSP and greatly reduce the HFP and the CIP.

Multi-Person Breathing Detection With Switching Antenna Array Based on WiFi Signal

WiFi sensing, an emerging sensing technology, has been widely used in vital sign monitoring. However, most respiration monitoring studies have focused on single-person tasks. In this paper, we propose a multi-person breathing sensing system based on WiFi signals. Specifically, we use radio frequency (RF) switch to extend the antennas to form switching antenna array. A reference channel is introduced in the receiver, which is connected to the transmitter by cable and attenuator. The phase offset introduced by asynchronous transceiver devices can be eliminated by using the ratio of the channel frequency response (CFR) between the antenna array and the reference channel. In order to realize multi-person breathing perception, we use beamforming technology to conduct two-dimensional scanning of the whole scene. After eliminating static clutter, we combine frequency domain and angle of arrival (AOA) domain analysis to construct the AOA and frequency (AOA-FREQ) spectrogram. Finally, the respiratory frequency and position of each target are obtained by clustering. Experimental results show that the proposed system can not only estimate the direction and respiration rate of multi-person, but also monitor abnormal respiration in multi-person scenarios. The proposed low-cost, non-contact, rapid multi-person respiratory detection technology can meet the requirements of long-term home health monitoring.

Joint Antenna and Device Scheduling in Full-Duplex MIMO Wireless-Powered Communication Networks

In this article, we study a joint antenna and Internet of Things device (ID) scheduling problem in the full-duplex (FD) multiple-input–multiple-output (MIMO) wireless-powered communication network (WPCN) over time-varying fading channels. We first formulate an optimization problem to maximize the average sum rate of IDs while satisfying their minimum average data rate requirements by jointly scheduling ID selection for uplink data transmission, antenna switching, and beamforming. To deal with the problem, we propose a scheduling algorithm based on Lagrangian duality and the stochastic optimization theory. The proposed scheduling algorithm necessitates solving per-time-slot problems, each of which aims at maximizing the weighted sum of the selected ID’s uplink data rate and the nonselected IDs’ harvested power from the downlink by jointly optimizing ID selection, antenna switching between uplink and downlink, and beamforming at that time slot. To solve the per-time-slot problem, we develop a joint ID selection, antenna switching, and beamforming (Joint-IAB) algorithm based on the block coordinate descent (BCD) and successive convex approximation (SCA) methods. Through simulation, we demonstrate that our scheduling algorithm with the proposed Joint-IAB algorithm provides better performance than the other scheduling algorithms while well satisfying the given minimum average data rate requirements of IDs.

Robust Analog Beamforming for Periodic Broadcast V2V Communication

We generalize an existing low-cost analog signal processing concept that takes advantage of the periodicity of vehicle-to-vehicle broadcast service to the transmitter side. In particular, we propose to process multiple antennas using either an analog beamforming network (ABN) of phase shifters, or an antenna switching network (ASN) that periodically alternates between the available antennas, to transmit periodic messages to receivers that have an analog combining network (ACN) of phase shifters, which has been proposed in earlier work. To guarantee robustness, we aim to minimize the burst error probability for the worst receiving vehicular user, in a scenario of bad propagation condition that is modeled by a single dominant path between the communicating vehicles. In absence of any form of channel knowledge, we analytically derive the optimal parameters of both ABN and ASN. The ABN beamforming vector is found to be optimal for all users and not only for the worst receiving user. Further, we demonstrate that Alamouti scheme for the special case of two transmit antennas yields similar performance to ABN and ASN. At last, we show that the derived parameters of the two proposed transmission strategies are also optimal when hybrid ACN-maximal ratio combining is used at the receiver.

Switching-Based Selection Techniques for Tripolar Antennas in Multihop IoT Networks

Adaptive multielement antennas can be leveraged to improve the reliability of wireless systems deployed in cluttered, depolarizing environments, such as those expected for Internet of Things (IoT) applications. While the performance improvement provided by such antennas has been well studied for individual links, multiple-hop networks have received little attention. In this work, we consider the problem of how devices in a multihop network should configure a three-element, tripolar antenna when deployed in a Rayleigh fading environment. We propose two switching-based antenna selection strategies: 1) Max-Sum and 2) Max–Min, each of which considers the channel conditions for communicating to nodes both higher and lower in the network hierarchy. We first derive the outage performance of the proposed schemes analytically and compare their performance with the well-known approaches of selection and switched diversity. Through simulations, which utilize empirical channel data from IoT devices equipped with a tripolar antenna, we show that the proposed Max-Sum and Max-Min schemes reduce antenna switching by over 80%, when compared to selection diversity. In addition, these two approaches lead to a median gain of 1.8 and 0.3 dB and a 1% diversity gain of 3.6 and 1.4 dB, respectively, relative to switched diversity.

Pseudo-doppler aided cancellation of self-interference in full-duplex communications

In this work, a novel scheme is proposed to enhance the self-interference (SI) cancellation in full-duplex communications. Beyond conventional SI cancellation schemes that rely on the SI suppression, our proposed scheme exploits periodic antenna switching to generate the pseudo-Doppler effect, thus completely removing the SI at the fundamental frequency. In this way, the desired signal is readily obtained through a low-pass filter. For the purpose of performance evaluation, the SI cancellation capability is defined as the difference between the output signal-to-interference-plus-noise ratio (SINR) and the input SINR. Theoretical formulations and numerical results validate that our pseudo-Doppler aided scheme has higher SI cancellation capability than the conventional SI suppression schemes. Moreover, the impact of the SI suppression achieved by conventional schemes and the influence of antenna switching timing difference on the practical implementation of the proposed scheme are investigated, to further substantiate the validity of our pseudo-Doppler aided SI cancellation.

Wireless Powered Relay Networks: Rate Optimal and Power Consumption-Aware WPT/SWIPT

We focus on the rate-optimal design of Wireless Powered Relay Networks (WPRNs) and propose a new cooperative communication scheme. Our scheme employs multiple wireless powered Amplify and Forward (AF) relays and relay selection and combines Time Splitting (TS), with Antenna Switching (AS) and Self Energy Recycling (SER). It consists of an initial Wireless Power Transfer (WPT) subframe, followed by a cooperative transmission subframe, during which one antenna is used for Energy Harvesting (EH) and SER and the remaining ones are used for data reception and data forwarding. For this scheme, we present solutions to the problems of 1) rate-optimal beamforming (BF) design, 2) rate-optimal, joint Harvesting Antenna Selection (HAS), BF design, and WPT subframe duration determination. Our solutions build on a generic piecewise linear EH model, which allows us to closely approximate the characteristics of different non linear EH measurements and models, by selecting the number of piecewise linear components and their parameters. In addition, we consider a realistic power consumption model at the relays that accounts for both transmit and circuit power consumption. Moreover, our BF solution is optimal and requires solving a set of simple optimization problems, where the solution of each one of them can be found in a simple closed form. Thus, it is characterized by low implementation complexity, and avoids sophisticated iterative optimization methods. To the best of our knowledge, this work is the first one to introduce a scheme, which combines TS, AS, and SER principles and exploits realistic EH and power consumption models at the relays. Finally, we assess the performance of our scheme over fading channels and find that it outperforms existing solutions that use the same hardware.

Another Perspective on Interference Channels for Non-Orthogonal Multiple Access Communications

In this letter, a new perspective on non-orthogonal multiple access (NOMA) is given, relying on the established model of interference channels (IC) from information theory. Establishing links with studies on ICs enables a new framework for the application of NOMA, especially in the context of distributed antenna systems. Thanks to this common framework, a fair and comprehensive evaluation of single antenna NOMA and IC-based NOMA is provided first. Then, a simple transmit coordination scheme, termed <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">antenna switching</i> , is proposed to switch the IC scenario from strong to weak IC leading to an increase in the achievable capacity under some system and channel conditions. Finally an application example is provided to show the advantage of the proposed approach that enables to match the type of NOMA to the deployment context according to the desired trade off between system throughput and user fairness.