Antenna Switching Research Articles

Negative charge-pump based antenna switch controller using 0.18 µm SOI CMOS technology

An antenna switch controller integrated with single-pole-multi-throw RF switches is presented. It is implemented in a 0.18 µm CMOS thin-film silicon-on-insulator (SOI) process. The proposed switch controller generates a negative voltage to enhance the linearity and power-handling capability of CMOS antenna switches, resulting in excellent RF performances. The size of the controller is 0.35 mm2 and the power consumption is 2 µA for stand-by mode and 50 µA for Rx mode.

Study of Conformal Switchable Antenna System on Cylindrical Surface for Isotropic Coverage

A conformal switchable antenna system mounted on a cylindrical surface is proposed, simulated, prototyped and measured. The antenna system is composed of several tri-polarization antennas operating at 2.4 GHz band. It is shown that this antenna system realizes a quasi-isotropic pattern without any nulls over a complete spherical surface. Specifically, it is shown that by using three tri-polarization antennas and switching among them, a complete spherical coverage could be achieved without any nulls and with a power gain larger than 2.5 dBi over more than 90 percent of a spherical surface surrounding the antenna system. Furthermore, it is shown that the performance of the antenna system does not deteriorate with the increase in the diameter of the mounting cylinder, thus facilitating the implementation of the proposed design in many applications including telemetry, satellites, and aircraft. Both simulation and experimental results of the radiation patterns are presented in this paper.

Design of a wideband multi-standard antenna switch for wireless communication devices

A wideband Low Power Single Pole 6-Throw (SP6T) antenna switch has been designed for GSM/DCS/802.11b mobile standards using a newly improved architecture and fabricated using a pseudomorphic depletion mode 0.18μm HEMT GaAs process. The switch exhibits less than 1dB insertion loss and isolation performances from up to 53dB at 0.8GHz down to 42dB at 2.5GHz. The circuit DC power consumption is less than 500μW in full power transmission condition and makes it suitable for use in mobile terminals like mobile phones or PDAs. The paper presents simulation results validated by experimental measurements on an IC prototype.

Cognitive maritime wireless mesh/ad hoc networks

Cognitive maritime wireless mesh/ad hoc networks are proposed in this paper, for the purpose to provide high-speed and low-cost communications for the current maritime users by incorporating the licensed but unused frequency bands opportunistically. Compared to other technologies, this scheme offers advantages of plenty of available bandwidth, easy installation, easy coverage extension, and high resilience. Nodes design requirements, possibly available frequency bands, regulation requirements, operation standards, and maritime communication challenges of the proposed networks are introduced and analyzed. A cognition-enhanced mesh medium access control (MAC) protocol for the operation of the proposed cognitive maritime mesh/ad hoc networks is presented, as well as a routing protocol and a switching antenna design that are capable of meeting the maritime challenges. Simulation results show that a higher detection probability and a longer sensing interval are both helpful to achieve better network performance, especially in case of high sea state. The operators need to find balance among cost, network performance, and protection of incumbents in the operation of the networks.

Compensating for the influence of human hand with two switchable antennas

A human hand or head in close proximity to a mobile terminal antenna causes impedance mistuning between the antenna and radiofrequency electronics, and absorption in the human tissue, deteriorating overall performance. This study aimed to clarify whether a two-antenna solution can reduce this effect, compared to a single-antenna solution. The studied two-antenna solution included placing switchable antennas both at the top and the bottom of a mobile terminal. User hand-induced performance deterioration was measured with a near field antenna measurement system, using a commercial hand phantom to model four different hand grips. The research covered the 824-894-MHz and 1850-2170-MHz frequency bands. The results of this study confirmed that the presence of a human hand weakens the antenna performance, especially in the lower frequency band. The total efficiency was improved by 2-9-dB for the lower band and by 1-2-dB for the higher band when using two switchable antennas instead of a single antenna. This study provides new understanding on compensating absorption losses. Terminal designers can utilise the results of this study when optimising antenna solutions.

Signal Modeling and Analysis of a Planar Phased-Array FMCW Radar With Antenna Switching

A frequency-modulated continuous-wave (FMCW) radar system with a planar phased array based on antenna switching is considered. The radar system consists of N1 linear antenna arrays where each linear antenna array consists of N2 receiving antennas. In each cycle, the receiving antennas on each linear antenna array are switched to the single receiving channel in turn from the first antenna to the N2th antenna. An accurate and detailed system model for the radar system is addressed. The Cramer-Rao lower bound (CRLB) analysis on the accuracy of estimating the azimuth angle, elevation angle, velocity, and range using the radar system is presented.

Linear polarisation switchable ring-slot array antenna using single-pole double-throw switch circuit

A linear polarisation switchable ring-slot array antenna is presented. The antenna is comprised of a four-element ring-slot array and a single-pole double-throw (SPDT) switch circuit. The linear polarisation switchable function is achieved using the SPDT switch circuit. Two Schottky barrier diodes are mounted on a slot ring of the SPDT switch circuit. Since the orthogonal linear polarisation switching depends on the diode ON/OFF conditions, the polarisation angle is easily controlled by the polarity of the bias voltage. The excellent design flexibility of double-sided microwave integrated circuit technology is effectively employed in forming this type of antenna. Experimental results show that the proposed antenna has good polarisation characteristics for the two orthogonal linear polarisations. The radiation performances of the two orthogonal polarisations are almost identical. Consequently, a linear polarisation switchable ring-slot array antenna is successfully verified.

Switchable Microstrip Antenna with Circular Polarization Diversity

In this letter, a novel design of a switchable microstrip antenna is proposed for circular polarization diversity. The proposed antenna has a simple construction of inner and outer corner-truncated radiating circular patches for switchable circular polarization. By controlling the state of two PIN diodes, left- and right-hand circular polarizations are easily alternated. The results of experiments show excellent switching radiation performances at the resonant frequency and good agreements with the simulated ones.

Reconfigurable L/S band phased array

A concept for reconfigurable L/S band phased arrays with a frequency switchable antenna element is presented. It is demonstrated with full-wave simulations that the proposed array structure is suitable for a wide angle scan in both frequency bands.

Design and Performance of Intergate-Channel-Connected Multi-Gate pHEMT for Antenna Switch

Conventional multi-gate pseudomorphic high-electron-mobility transistors (pHEMTs) in the off-state generate larger distortion than single-gate pHEMTs in RF switch applications. To reduce the distortion, the intergate region of multi-gate pHEMTs must be connected to the source and drain with resistors to be biased at the same DC voltage. The intergate region of multi-gate pHEMTs is too small to have an external electrical contact, so intergate-channel-connected pHEMTs (IGCC-pHEMTs) have been developed. IGCC-pHEMTs have a meander gate structure, where one side of the gate is connected to a metal wire layer, and the other is applied for an intergate region contact that does not widen the distance between the gates. A single-pole double-throw (SPDT) switch with IGCC-pHEMTs was fabricated by using a standard 0.5µm InGaAs pHEMT process. A SPDT switch with IGCC-pHEMTs is confirmed to have almost same small-signal properties and generate lower distortions.

Dose reconstruction using mobile phones

Electronic components inside mobile phones are regarded as useful tools for accident and retrospective dosimetry using optically stimulated luminescence (OSL) and thermoluminescence. Components inside the devices with suitable properties for luminescence dosimetry include, amongst others, ceramic substrates in resistors, capacitors, transistors and antenna switches. Checking the performance of such devices in dosimetric experiments is a crucial step towards developing a reliable dosimetry system for emergency situations using personal belongings. Here, the results of dose assessment experiments using irradiated mobile phones are reported. It will be shown that simple regenerative dose estimates, derived from various types of components removed from different mobile phone models, are consistent with the given dose, after applying an average fading correction factor.

Distributed space-time coded non-orthogonal DF protocols with source antenna switching

In this paper, a new distributed space-time coded (DS-TCed) non-orthogonal decode-and-forward (NDF) protocol with source antenna switching (SAS) is proposed, where two antennas associated with each radio frequency chain can be alternatively used in the first and second phases. Several DSTC schemes for the NDF with SAS (NDF-SAS) protocol are proposed and their average pairwise error probability for the error-free source-relay (SR) channel is also derived. The simulation results show that the NDF-SAS protocol achieves larger diversity order than the NDF protocol under the error-free and erroneous SR channels.

Terahertz Time Domain Spectroscopy, T-Ray Imaging and Wireless Data Transfer Technologies

This study reviewed terahertz technologies of time domain spectroscopy, T-ray imaging, and high rate wireless data transfer. The main topics of the terahertz research area were investigation of materials and package modules for terahertz wave generation and detection, and setup of the terahertz system for time domain spectroscopy(TDS), T-ray imaging and sub-THz wireless communication. In addition to Poly-GaAs film as a photoconductive switching antenna material, a table-top scale for the THz-TDS/imaging system and terahertz continuous wave(CW) generation systems for sub-THz data transfer and narrow band T-ray imaging were designed. Dielectric properties of ferroelectric BSTO(<TEX>$Ba_xSr_{1-x}TiO_3$</TEX>) films and chalcogenide glass systems were characterized with the THz-TDS system at the THz frequency range. Package modules for terahertz wave transmitter/receiver(Tx/Rx) photoconductive antenna were developed.

ARQ-Aided Downlink Time Switched Transmit Diversity with Power Ramping in the WCDMA LCR-TDD System

This paper investigates the performance of ARQ-aided downlink Time Switched Transmit Diversity (TSTD) in the WCDMA Low Chip Rate (LCR)-Time Division Duplex (TDD) system, when antenna switching and power ramping are applied. With the help of the ARQ signal, where the receiver sends the acknowledgement (ACK or NACK) to the transmitter, the proposed TSTD scheme switches the transmit antenna and ramps up the transmission power for the retransmitted data, when the transmitter receives a NACK signal. Simulation results demonstrate, that when the mobile speed is 3km/h and a frame error rate (FER) is set to 1%, the antenna switching scheme yields 2dB to 3dB performance gain in terms of average Eb/N0, and the power ramping gives 0.7dB to 1.6dB gain, compared with the conventional ARQ-aided TSTD. In addition, 6% of throughput gain is shown by amalgamating the antennas switching as well as the power ramping, when the average Eb/N0 is equal to 0dB.

Antenna Switching Schemes for Downlink Time Switched Transmit Diversity with ARQ in Rayleigh Fading Channels

For automatic repeat request (ARQ)-aided TSTD (Time Switched Transmit Diversity) system, a receiver sends the acknowledgement signal (ACK or NACK) to a transmitter in order to predict the condition of the channel. In this paper, two antenna switching schemes, in which the NACK trigger the transmit antenna switching in the proposed antenna switching patterns, are proposed for the TSTD with the ARQ in WCDMA LCR-TDD systems. In addition, the system performances are investigated. Simulation results demonstrate that the performances of the TSTD systems can be improved by applying the ARQ scheme. Furthermore, the performances of ARQ-aided TSTD systems may be significantly improved by applying the proposed antenna switching schemes, especially when the mobile's speed is low.

Charge Pump Circuits: An Overview on Design Strategies and Topologies

Due to the continuous power supply reduction, charge pumps circuits are widely used in integrated circuits (ICs) devoted to several kind of applications such as smart power, nonvolatile memories, switched capacitor circuits, operational amplifiers, voltage regulators, SRAMs, LCD drivers, piezoelectric actuators, RF antenna switch controllers, etc. The main focus of this tutorial manuscript is to provide a deep understanding of the charge pumps behavior, to present useful models and key parameters and to organically and in details discuss the optimized design strategies. Finally, an overview of the main different topologies is also included.

A Beam Switching Planar Yagi-patch Array for Automotive Applications

In this work, a planar beam switching antenna is proposed for wireless commu- nication used in automotive environment. By integrating a Yagi patch antenna array with a one-to-four RF switch, RF power can be delivered to four difierent driven patch elements and generate directive beams toward difierent directions. The prototype antenna is designed to op- erate at the GSM 1800/1900MHz band for cellular phone uses. The size and height of the fabricated antenna are 293mm by 293mm by 3mm, respectively. Measurement results indicate the antenna's gain is approximately 9.478dBi with a 3dB beamwidth of 68 - . 1. INTRODUCTION Due to the rapid growth of wireless communication applications, interference and multi-path fading phenomena become critical and need to be resolved to ensure communication quality. In this paper, a planar beam switching antenna, which is a combination of logic control circuits, a one-to-four RF switch, and Yagi patch antennas (1{5) are proposed to provide spatial diversity. The antenna conflguration is shown in Fig. 1. The Yagi patch comprises four driven patch elements, which are connected via a one-to-four RF switch and flve parasitically coupled director patch elements. By selecting a speciflc through path of the RF switch, RF power is fed to one of the driven patch elements. Because directive radiating elements are used, the antenna can be reconflgured to four difierent beam directions and therefore reduces potential blind angles. Since the antenna comes with a planar structure, it can be employed in the automotive environment. For instance, the planar antenna can be mounted on top of a vehicle. The switching directive beam enables the moving vehicle to track a speciflc base station and extends the communication distance. Such a planar beam switching antenna can also be used for mobile devices to ensure connection quality. The design procedure and geometric parameters of the planar one-to-four beam switching an- tenna are presented in Section 2. The measured antenna performance, including the operational frequency, gain, 3dB beamwidth, and the squint angle, are provided in Section 3. Analysis based on the comparison of simulated and measured results is also given. A brief summary is drawn at the end.

평면형 능동 위상 배열 레이더용 안테나 시스템 개발

본 논문에서는 레이더용 평면형 능동 위상 배열 안테나 시스템의 설계 및 제작 그리고 측정 결과를 소개한다. 설계된 안테나는 X-대역에서 대역폭 10 %를 만족하며, 이중 슬롯 급전 마이크로스트립 패치 안테나와 편파 스위치의 사용으로 이중 편파 사용이 가능하다. 배열 구조는 <TEX>$16\times16$</TEX>의 삼각 배열 구조이고, 각 배열은 출력 40 dBm 이상의 TR(Transmit & Receive) 모듈로 구성된다. TR 모듈은 디지털 감쇄기와 위상 변위 기를 포함하고 있어서 임의의 빔 형성/빔 조향을 할 수 있으며, 전자적 빔 조향 범위는 방위각/고각 방향으로 각각 <TEX>${\pm}60^{\circ}$</TEX> 범위에서 가능하다. 또한 수신 구조는 부배열로 구성하여 수신 패턴은 각 채널로부터의 RF 빔 합성으로 얻어진다. 안테나의 성능 검증을 위해서 근접 전계 측정 시설에서 안테나 패턴을 측정하였으며, 패턴 측정 결과는 예측된 빔 패턴과 거의 일치하였고, 이로부터 제어에 의한 빔 조향/빔 형성이 가능함을 확인할 수 있었다. The design and implementation of planar Active Phased Array Antenna System are described in this paper. This Antenna system operates at X-band with its bandwidth 10 % and dual polarization is realized using dual slot feeding microstrip patch antenna and SPDT(Single Pole Double Through) switch. Array Structure is <TEX>$16\times16$</TEX> triangular lattice structure and each array is composed of TR(Transmit & Receive) module with more than 40 dBm power. Each TR module includes digital attenuator and phase shifter so that antenna beam can be electronically steered over a scan angle<TEX>$({\pm}60^{\circ})$</TEX>. Measurement of antenna pattern is conducted using a near field chamber and the results coincide with the expected beam pattern. From these results, it can be convinced that this antenna can be used with control of beam steering and beam shaping.

Nanoscale CMOS Transceiver Design in the 90–170-GHz Range

This paper reviews recent research conducted at the University of Toronto on the development of CMOS transceivers aimed at operation in the 90-170-GHz range. Unique nanoscale CMOS issues related to millimeter-wave circuit design in the 65-nm node and beyond are addressed with an emphasis on transistor and top-level layout issues, low-voltage circuit topologies, and design flow. A Doppler transceiver and two receivers fabricated in a 65-nm GPLP CMOS technology are described, along with a single pole, double throw antenna switch with better than 5-dB insertion loss and 25-dB isolation in the entire 110-170-GHz band. The first receiver has an IQ architecture with a fundamental frequency voltage-controlled oscillator, and is intended for wideband passive imaging applications at 100 GHz. The measured noise figure and downconversion gain are 7-8 and 10.5 dB, respectively, while the 3-dB bandwidth extends from 85 to 100 GHz. The second receiver has double-sideband architecture, operates in the 135-145-GHz range (the highest for CMOS receivers), and features an 8-dB gain LNA, a double-balanced Gilbert cell mixer, and a dipole antenna. The 90-94-GHz Doppler transceiver, the highest frequency reported to date in CMOS, is intended for the remote monitoring of respiratory functions. A Doppler shift of 30 Hz, produced by a slow-moving (4.8 cm/s) target located at a distance of 1 m, was measured with a transmitter output power of approximately + 2 dBm and a phase noise of -90 dBc/Hz at 1 MHz offset. The range correlation effect is demonstrated for the first time in CMOS by measuring the phase noise of the received baseband signal at 10-Hz offset, clearly indicating that 1/ <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> noise has been canceled and it does not pose a problem in short-range applications, where neither a phase-locked loop nor a frequency divider are needed.

A 1.8-GHz 33-dBm $P$ 0.1-dB CMOS T/R Switch Using Stacked FETs With Feed-Forward Capacitors in a Floated Well Structure

A 33-dBm P 0.1-dB single-pole double-throw antenna switch is designed and implemented using a standard 0.18-mum CMOS process at 1.8 GHz. An analysis shows a relation between parasitic junction capacitors and substrate resistance for low insertion loss (IL). The power-handling capability of the switch was also investigated through the voltage dividing mechanism through the substrate in the case of an ON-insertion loss-state NMOS switch implemented in a triple-well structure. A multistacked field-effect transistor (FET) structure with feed-forward capacitors in an Rx switch was chosen as the method of designing an antenna switch with high power-handling capability. Low IL of the switch in the multistacked FET structure is achieved by the optimization of layout and minimization of junction capacitors through the deep N-well bias. Allowance of a negative voltage swing at either the source or drain port is ensured by a floated well structure with a negatively biased P-well for each switch device of the multistacked FET structure. Intentional unequal division of the voltage swing level at each NMOS device by feed-forward capacitors with negative biases of the off-state switches helps to prevent channel formation in the off-state device. Experimental data shows that the proposed design achieves a 0.1-dB compression point at 33-dBm input power at 1.8 GHz with a negative bias supply to control the voltage at the off-state switches and the P -well of each device. The IL of the Tx switch is 0.5 and 0.73 dB at 900 MHz and 1.8 GHz, respectively. The Rx switch has 0.7- and 1.1-dB IL at 900 MHz and 1.8 GHz, respectively. In addition, a reliability issue related to antenna load mismatch was tested using a load-pull measurement setup.