Antenna Switching Research Articles

Microsecond switchable thermal antenna

We propose a thermal antenna that can be actively switched on and off at the microsecond scale by means of a phase transition of a metal-insulator material, the vanadium dioxide (VO2). This thermal source is made of a periodically patterned tunable VO2 nanolayer, which support a surface phonon-polariton in the infrared range in their crystalline phase. Using electrodes properly registered with respect to the pattern, the VO2 phase transition can be locally triggered by ohmic heating so that the surface phonon-polariton can be diffracted by the induced grating, producing a highly directional thermal emission. Conversely, when heating less, the VO2 layers cool down below the transition temperature, the surface phonon-polariton cannot be diffracted anymore so that thermal emission is inhibited. This switchable antenna could find broad applications in the domain of active thermal coatings or in those of infrared spectroscopy and sensing.

A linear 180 nm SOI CMOS antenna switch module using integrated passive device filters for cellular applications

A broadband monolithic linear single pole, eight throw (SP8T) switch has been fabricated in 180 nm thin film silicon-on-insulator (SOI) CMOS technology with a quad-band GSM harmonic filter in integrated passive devices (IPD) technology, which is developed for cellular applications. The antenna switch module (ASM) features 1.2 dB insertion loss with filter on 2G bands and 0.4 dB insertion loss in 3G bands, less than −45 dB isolation and maximum −103 dB intermodulation distortion for mobile front ends by applying distributed architecture and adaptive supply voltage generator.

A Low Complexity Antenna Switching for Joint Wireless Information and Energy Transfer in MIMO Relay Channels

In this paper, we investigate a low-complexity technique for simultaneous wireless information and energy transfer in multiple-input multiple-output relay channels. The proposed technique exploits the array configuration at the relay node and uses the antenna elements either for conventional decoding or for rectifying (rectennas). In order to keep the complexity low, a dynamic antenna switching between decoding/rectifying is proposed based on the principles of the generalized selection combiner (GSC); the L strongest paths are allocated for decoding while the remaining channel paths for rectifying (and vice versa). The optimal L as well as the allocation strategy that minimizes the outage probability are investigated via theoretical and numerical results. In addition, two performance bounds that provide the optimal performance without the limitation of GSC are proposed by solving a linear programming and a binary knapsack problem, respectively. The proposed technique is extended to scenarios with multi-user interference, where a zero-forcing receiver is used at the relay node; closed-forms expressions for the outage probability are also derived.

Monolithic Single-Pole Sixteen-Throw T/R Switch for Next-Generation Front-End Module

A broadband monolithic linear single-pole, sixteen-throw (SP16T) antenna switch has been designed and fabricated in 180 nm thin film SOI CMOS process, which is intended for the next generation multimode multiband (MMMB) cellular applications. The switch features the minimum 0.7 dB and average 1dB insertion loss, 0.1 dB compression point of 29 dBm and at least 33 dB isolation at all cellular bands for mobile front ends by applying distributed architecture and adaptive supply voltage generator. To the best of our knowledge, this work is the first demonstration of SP16T antenna switch with superior isolation and power handling capacities for most of the known cellular bands with satisfactory harmonic and intermodulation distortion performance on SOI. The simulated and measured results show excellent agreement.

Degrees of Freedom Characterization: The 3-User SISO Interference Channel with Blind Interference Alignment

We characterize the degrees of freedom (DoF) of the 3-user Gaussian interference channel where each transmitter is equipped with a single conventional antenna and each receiver is equipped with one multi-mode antenna. By assuming that the channel is unknown to the transmitters and only known to the receivers, we show that by using linear blind interference alignment (BIA) with antenna switching at the receivers only, the sum DoF are 6/5. The new insight behind this result is that any vector of a user aligned at one unintended receiver cannot be aligned at the other unintended receiver. This is the first complete characterization of the sum DoF when using BIA over the Gaussian Interference Channel. The DoF result under the temporal correlated channels is also discussed.

Ultra-broadband terahertz time-domain ellipsometric spectroscopy utilizing GaP and GaSe emitters and an epitaxial layer transferred photoconductive detector

We present a reflection-type ultra-broadband terahertz (THz) time-domain spectroscopic ellipsometry system covering the frequency range of 0.5–30 THz. GaP (110) and z-cut GaSe crystals are used as emitters to generate the THz and mid-infrared pulses, respectively, and a photoconductive antenna switch using a low-temperature grown GaAs epitaxial layer transferred on Si substrate was used as a detector. By changing the emitter between the GaP and GaSe crystals, the measurable frequency range can be easily switched from the 0.5–7.8 THz range to the 7.8–30 THz range without additional optical alignment. We demonstrated the measurement of the dielectric function in a p-type InAs wafer and the optical conductivity of an indium tin oxide (ITO) thin film. The obtained carrier density and the mobility of the ITO thin film show good agreement with that obtained by the Hall measurement.

Multichannel microwave interferometer with an antenna switching system for electron density measurement in a laboratory plasma experiment

This study presents a simple and powerful technique for multichannel measurements of the density profile in laboratory plasmas by microwave interferometry. This technique uses electromechanical microwave switches to temporally switch the connection between multiple receiver antennas and one phase-detection circuit. Using this method, the phase information detected at different positions is rearranged into a time series that can be acquired from a minimum number of data acquisition channels (e.g., two channels in the case of quadrature detection). Our successfully developed multichannel microwave interferometer that uses the antenna switching method was applied to measure the radial electron density profiles in a magnetized plasma experiment. The advantage of the proposed method is its compactness and scalability to multidimensional measurement systems at low cost.

A wide range, high yield and good performance pHEMT switch for MMIC phase shifter

A low-cost method with high yield and good performance is presented by pHEMTs (pseudomorphic high electron mobility transistors) to be used in phase shifter switches. In this method, the capacitor in “off” mode (Coff) of transistor is reduced, without variation of the transistor structure. The transistor structure in switch mode can be optimised. This method increases the transistor isolation in turn “off” mode, while there is no change in resistance of the transistor in “on” mode (Ron). Transistor dimension is determined in turn “off” mode (Vg = −4.5 V) and standard form of 4 × 75 μm. So, in this method, insertion loss will be reduced without a perceptible change in transistor dimension. Thus, design and fabrication capability of some circuits such as phase shifters, antenna switches, SPDT (single port double throw) – without any change in technology – are increasing. In this paper, post layout and measurement result for a sample block of phase shifter are shown.

Parameters Analysis for the Time-Varying Automatically Adjusted LPA Based Estimators

The paper provides the performance analysis of the optimal parameters selection for the weighted local polynomial approximation (LPA) estimators combined by a data-driven adaptive method used for the automatically adjusted nonparametric LPA estimator size detection. The provided examples show that the LPA estimators upgraded by the modified adaptive intersection of the confidence intervals (ICI) based method (called the RICI method) outperform those based on the original ICI rule, while the ICI rule based LPA estimators were known to outperform non-adaptive ones with fixed size window length. The method’s performance is analyzed in noise environment for two signals, showing the modified ICI based LPA estimators to be superior to those based on the original ICI method in terms of denoising estimation error reduction. The method can be applied in various technical fields, including image and video filtering, beamforming for phased array radar with antenna switching, acoustic echo cancellation, instantaneous frequency estimation, etc. 

Modeling the NMR signatures associated with the functional conformational switch in the major light-harvesting antenna of photosystem II in higher plants

The major photosystem II antenna complex, LHCII, possesses an intrinsic conformational switch linked to the formation of a photoprotective, excitation-quenching state. Recent solid state NMR experiments revealed that aggregation-induced quenching in (13)C-enriched LHCII from C. reinhardtii is associated with changes to the chemical shifts of three specific (13)C atoms in the Chla conjugated macrocycle. We performed DFT-based NMR calculations on the strongly-quenched crystal structure of LHCII (taken from spinach). We demonstrate that specific Chla-xanthophyll interactions in the quenched structure lead to changes in the Chla(13)C chemical shifts that are qualitatively similar to those observed by solid state NMR. We propose that these NMR changes are due to modulations in Chla-xanthophyll associations that occur due to a quenching-associated functional conformation change in the lutein and neoxanthin domains of LHCII. The combination of solid-state NMR and theoretical modeling is therefore a powerful tool for assessing functional conformational switching in the photosystem II antenna.

Intelligent antenna selection decision in IEEE 802.15.4 wireless sensor networks: An experimental analysis

The goal of this paper is to study the feasibility of making intelligent antenna selection decision in IEEE 802.15.4 Wireless Sensor Networks (WSNs). This study provides us the basis to design and implement software defined intelligent antenna switching capability to wireless sensor nodes based on Received Signal Strength Indicator (RSSI) link quality metric. First, we discuss the results of our newly designed radio module (Inverted-F Antenna) for 2.4GHz bandwidth (WSNs). Second, we propose an intelligent antenna selection strategy to exploit antenna diversity. Third, we propose the prototype of our diversity antenna for the TelosB mote and the intelligent switch design. Finally, we compare the performance of the built-in TelosB antenna with our proposed external antenna in both laboratory and realistic environments. Experimental results confirm the gain of 6–10dB of the proposed radio module over the built-in radio module of the TelosB motes.

Use of OSL and TL of Electronic Components of Portable Devices for Retrospective Accident Dosimetry

Growing apprehensions of radiological accidents and terroristic attacks have intensified research efforts to find materials with appropriate radiation sensitivity that are carried close to human body, are ubiquitously available and which can be used as fortuitous dosimeters in rapid determination of doses of individuals after radiation exposure. In this respect, thermoluminescence (TL) and optically stimulated luminescence (OSL) of chip cards and electronic components of personal objects have been recently evaluated by researchers in several countries. OSL and TL signal of chip cards is attributed to SiO2 grains contained in the epoxy layers used for controlling the thixotropic properties whereas the radiation induced signal in electronic components (resistors, resonators, capacitors, ICs, antenna switches, etc.) of personal objects (mobile phones, USB flash drive, MP3 players, etc.) is attributed to the ceramic contents, especially to Al2O3 based substrates.

Outage Probability and Energy Efficiency of Cooperative MIMO with Antenna Selection

This paper compares the energy efficiency of some cooperative MIMO schemes in wireless networks. By energy efficiency we denote the spectral efficiency seen at the receiver normalized by the total energy consumption, which includes the circuitry, the efficiency of the power amplifier, and the transmission rate. We focus on transmit antenna selection (TAS) and switch and stay combining (SSC) at the receiver. The performance of TAS+SSC is compared to that of TAS and maximal ratio combining (MRC), and to that of transmit/receive beamforming using a singular value decomposition (SVD) technique. We derive closed-form outage probability expressions, and analyze the effect of selecting the antenna from the source to optimize the communication with the relay or with the destination. Our results show that selecting the antennas with respect to the destination is in general a better option when the energy consumption is accounted. Moreover, some power allocation strategies are described and the comparison of the schemes in terms of energy efficiency reveals a considerable improvement with the use of TAS+SSC for low to moderate spectral efficiency, while beamforming outperforms the other schemes for high spectral efficiency when the number of antennas at each node is small.

A Novel Interference Alignment Scheme Based on Sequential Antenna Switching in Wireless Networks

Interference alignment (IA) is a promising technique that can effectively eliminate the interference in wireless networks. However, in traditional IA schemes, the signal to interference plus noise ratio (SINR) may significantly degrade, and the quality of service (QoS) may be unacceptable. In this paper, a novel IA scheme based on antenna switching (AS-IA) is proposed to improve the SINR of the received signal while guaranteeing the QoS in IA wireless networks. In the proposed scheme, some of the antennas are replaced by reconfigurable ones that can switch among preset modes, and the best channel coefficients are selected. Furthermore, to reduce the computational complexity, a sequential antenna switching IA (SAS-IA) scheme is proposed with only one antenna switching in each time slot, and the communication proceeds during the process of searching for the optimal solution. To further improve the performance of the SAS-IA scheme under imperfect channel state information (CSI), a filtering SAS-IA scheme is proposed through averaging the estimated CSI during the iterations of the distributed IA algorithm. Simulation results are presented to show the effectiveness and efficiency of the proposed schemes in improving the QoS of IA wireless networks.

TRITON: high-speed maritime wireless mesh network

This article presents the TRI-media Telematic Oceanographic Network (TRITON) project, which aims to develop a high-speed and low-cost maritime communication system. The article includes information pertaining to background studies, high-level architecture, network feasibility, maritime communication environment, technology developments, prototype implementations and link performance measurements. The motivation for this project stems from the fact that there is an increasing need for low-cost and high-speed maritime communication, with demands mainly coming from regulatory and crew welfare needs. The system described in this article is a wireless mesh network based on the IEEE 802.16. An analysis of the node connectivity based on real ship traffic data shows that the network is feasible in shipping lanes with a high density of ships. The system also considers the use of an intelligent middleware to allow communications to switch back to a satellite link in cases where neighboring ships are sparse or at locations far away from mesh base stations. Protocol enhancements to both the Medium Access Control (MAC) and networking layers and a hardware design that features multiple transceivers and the implementation of antenna switching to counter sea wave reflection and rocking problems are presented. Measurements of field trials show that the proposed wireless mesh network could be an effective solution for maritime communications.

Wireless Information and Power Transfer: A Dynamic Power Splitting Approach

Energy harvesting is a promising solution to prolong the operation time of energy-constrained wireless networks. In particular, scavenging energy from ambient radio signals, namely wireless energy harvesting (WEH), has recently drawn significant attention. In this paper, we consider a point-to-point wireless link over the flat-fading channel, where the receiver has no fixed power supplies and thus needs to replenish energy via WEH from the signals sent by the transmitter. We first consider a SISO (single-input single-output) system where the single-antenna receiver cannot decode information and harvest energy independently from the same signal received. Under this practical constraint, we propose a dynamic power splitting (DPS) scheme, where the received signal is split into two streams with adjustable power levels for information decoding and energy harvesting separately based on the instantaneous channel condition that is assumed to be known at the receiver. We derive the optimal power splitting rule at the receiver to achieve various trade-offs between the maximum ergodic capacity for information transfer and the maximum average harvested energy for power transfer, which are characterized by the boundary of a so-called "rate-energy (R-E)" region. Moreover, for the case when the channel state information is also known at the transmitter, we investigate the joint optimization of transmitter power control and receiver power splitting. The achievable R-E region by the proposed DPS scheme is also compared against that by the existing time switching scheme as well as a performance upper bound by ignoring the practical receiver constraint. Finally, we extend the result for optimal DPS to the SIMO (single-input multiple-output) system where the receiver is equipped with multiple antennas. In particular, we investigate a low-complexity power splitting scheme, namely antenna switching, which achieves the near-optimal rate-energy trade-offs as compared to the optimal DPS.

A Novel Beam Steering of Hybrid Switchable Beam Textile Antenna

A novel hybrid switchable beam textile antenna (HSBTA) is proposed in this research. The HSBTA introduced by a coaxial probe technique to feed current flow to center of HSBTA and distribute the current to four circles of radiating elements. This research found that the integration of RF switches and electronic components is successfully embedded into wearable textile antenna using a silver-conductive epoxy adhesive. The four RF switches are then incorporated at four ideal locations of HSBTA's circle radiating elements to generate the beam steering ability with directivity as high as 6.8 dBi. With the help of particular RF switching scheme, the HSBTA has successfully tailored the beam to four different angles of 0°/360°, 90°, 180°, and 270° at single operating frequency of 2.45 GHz. Dimensionwise, 88 × 88 mm2 could lead the HSBTA to be deployed on smart garment for wireless body area network application. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1893–1897, 2013

입력-결합 전류 제한 링 발진기와 하드웨어 효율적인 레벨 시프터를 적용한 저전력 안테나 스위치 컨트롤러 IC

In this paper, a low power antenna switch controller IC is designed using a silicon-on-insulator (SOI) CMOS technology. To improve power handling capability and harmonic distortion performance of the antenna switch, the proposed antenna switch controller provides 3-state logic level such as +VDD, GND, and -VDD for the gate and body of switch of FETs according to decoder signal. By employing input-coupled current ring oscillator and hardware efficient level shifter, the proposed controller greatly reduces power consumption and hardware complexity. It consumes 135 at a 2.5 V supply voltage in active mode, and occupies in area. In addition, it shows fast start-up time of 10 .

A directional MAC for switchable directional antennas to enhance throughput in crowded infrastructure wireless networks

In conventional infrastructure wireless networks, access points and nodes use omni-directional antennas. In a crowded situation, users have experienced throughput degradation due to various reasons. In this paper, we propose wireless LANs equipped with switchable directional antennas and a directional MAC protocol designed for them. In the proposed wireless LAN, every node including access point is always engaged in directional transmission and reception, but a node is allowed to receive omni-directionally only for association process. This new system enhances throughput in overlapped multiple basic service sets by reducing interference, increasing spatial reuse, and avoiding transmission loss phenomenon TLP. The simulation results show that the proposed protocol outperforms conventional IEEE 802.11 DCF, in terms of throughput in crowded infrastructure wireless networks.

High Resolution 2-D DOA Estimation by Low-Cost Antenna Array Based on Synthesized Covariance Matrix via Antenna Switching

High Resolution 2-D DOA Estimation by Low-Cost Antenna Array Based on Synthesized Covariance Matrix via Antenna Switching