A Beam-Steering Broadband Microstrip Antenna with High Isolation

In this paper, a 4.2–7.2 GHz(52.6%)beam-steering microstrip antenna was proposed. The proposed antenna consists of three tapered slots and feeds.The three radiation directions of the antenna on the plane are independent of each other, and the three feeds correspond to the three radiation structures. Symmetry isolation trenches are introduced to improve isolation between different ports. Radiation pattern simulation and measurement show horizontal beam steering at the sampled frequencies of 4.2, ...     

A Novel Single-Feed Circular Microstrip Antenna With Reconfigurable Polarization Capability

A single-feed circular microstrip antenna with reconfigurable polarization capability is proposed. This antenna has a simple structure, which consists of a radiating circular patch, five switches (PIN diode), three matching stubs, and a 50 microstrip feed line. It can be switched between 4 different states: two states (low-frequency and high-frequency) for linear polarization (LP), one state for left hand circular polarization (LHCP) and one for right hand circular polarization (RHCP) by controlling the bias voltage of two PIN diodes. At the same time, three switchable matching stubs are used for matching every polarization state. Simulation results and experimental results show that the proposed antenna demonstrates a low cross polarization level, good impedance bandwidth, and a very good axial ratio in the circularly polarized states.     

唯相位方法实现方向图可重构阵列天线

使用唯相位方法设计方向图可重构天线,对阵列的激励电流幅度和相位同时进行优化,得到一组电流幅度值,使它适用于多种形状的方向图,同时得到与每种方向图对应的相位值。优化算法选用实数编码的遗传算法。为了把设计结果应用于实践,文中还对电流幅度的分布进行了一定的限制,设计出了具有2种工作状态的方向图可重构天线,最后给出了仿真结果,结果表明,文中讨论的方法在设计方向图可重构天线方面是有效的。     

Pattern Reconfigurable Cubic Antenna

A new single-feed reconfigurable antenna for pattern diversity is presented in this paper. The proposed structure is based on a metallic cubic cavity which radiates through rectangular slots. The pattern reconfiguration is achieved with PIN diode switches by short-circuiting slots in their center. The designed antenna can switch between three different radiation patterns which radiate in a $4pi$ steradian range and can receive any incident field polarizations. A prototype of the antenna, including PIN diodes and operating in the 5 GHz band, has been built to demonstrate the feasibility of the concept. Measurements have been conducted and three-dimensional radiation patterns are provided. Diversity performances are evaluated by calculating the envelope correlation coefficient.      

Reconfigurable Microstrip Patch Antenna with Switchable Polarization

A novel reconfigurable microstrip patch antenna with frequency and polarization diversities is proposed. A U‐slot is incorporated into a square patch, and a PIN diode is utilized to switch the slot on and off, which realizes the frequency diversity characteristic. The polarization diversities among linear polarization (LP), right‐hand circular polarization (RHCP), and left‐hand circular polarization (LHCP) are also obtained by switching three PIN diodes on the slot and the truncating corners of a square patch on and off. The antenna design and experimental results are presented.     

极化可变可重构微带天线

设计了一种单点馈电的小型微带正方形贴片开槽天线,通过控制二极管的开关状态改变贴片上两个相互正交开槽的状态,可以实现左旋与右旋圆极化的切换.文中给出了Ansoft HFSS9.0的仿真结果和实测结果.仿真与测试结果表明,这种极化可变可重构微带天线具有较好的圆极化特性,可以应用于无线通讯与卫星通信领域.     

基于极化可重构天线的天线选择方案

天线选择是降低多天线通信系统的硬件复杂度以及改善空域相关性能的有效途径,但对于天线安装空间受限的小型终端,天线的数目将受到很大限制,从而制约了天线选择算法的实施.本文提出一种基于极化可重构天线的天线选择方案,该方案具有紧凑的天线结构和低复杂度的选择算法,适合于小型移动终端使用;通过理论以及数值仿真实验,证明了该方案能明显提高系统性能.     

一种新型圆极化可重构天线

本文利用最大功率传输效率法(MMPTE),通过4个相同左旋圆极化贴片单元作为子阵来实现阵列天线圆极化可重构.通过在被设计阵列(作为发射阵列)远场区引入极化控制接收天线,可以将整个收发系统看作一个无线功率传输系统,这样就可以把阵列天线的设计问题转换为一个天线之间的传输效率最优化的问题.通过调节接收天线的极化方式和接收位置...     

一种具有陷波特性的多模态频率可重构UWB天线

为了应对在超宽带(Ultra-Wide Band, UWB)系统中频率可重构天线尺寸偏大、模式单一等问题,提出了一种具有陷波特性的多模态频率可重构UWB天线。该天线通过在圆形单极子的辐射贴片上添加T型枝节和刻蚀I型槽、倒U型槽,以获得UWB覆盖范围为2.7～11.6 GHz的宽阻抗带宽,并产生四个陷波带。仿真与实测表明：控制PIN二极管的偏置状态,可以实现单频段、双频段、三频段、四频段和五频段共五种频段下八种工作模式的多模态切换。此天线大小为16 mm×19 mm,较传统单极子天线体积减小了40%以上,实现了小型化。天线的最大增益为4.13 dBi,具有良好的辐射特性。     

五元印刷单极子方向图可重构阵列天线*

设计制作了一种用于无线通信移动终端的方向图可重构阵列天线.该阵列天线由一个激励单极子和四个长度可调的寄生印刷单极子组成,可工作于两种模式,阵列波束在方位面内有八种不同的指向.通过控制PIN开关的状态,寄生单元可以在引向器和反射器之间切换状态,方向图的主瓣指向开关断开的阵元方向.阵列天线方向图可以以45°步长覆盖方位面,工作频带覆盖WiMAX (3.40-3.69GHz)频段,辐射增益大于6dBi.在两种模式中各选取了一个指向状态,对其回波损耗和方向图进行了实测,实测结果与仿真结果吻合较好.     

A Beam-Steering and -Switching Antenna Array Using a Coupled Phase-Locked Loop Array

We present the analysis and experimental results of a beam-steering and -switching antenna array using coupled oscillators and phase-locked loops. With the use of a type-II coupled phase-locked loop array and an external reference signal, the antenna array can steer its beam by a single control voltage, reduce the beam-pointing error arising from the phase errors of the oscillator array, and hold its output frequency stably at the reference signal frequency in operation. Using a double-pole double-throw switch and a difference amplifier at the center element of the antenna array, one can switch the array radiation pattern between the sum pattern and the difference pattern. Moreover, the beam-scanning range is extended to plusmn 90deg by properly using frequency prescalers in the phase-locked loops. The radiation characteristics of a three-element antenna array are measured to verify the array performance.     

一种新型极化可重构微带天线

利用互补开口谐振环(CSRR)结构提出了一种新型极化可重构微带天线。将CSRR 和一个PIN 二极管开关加载在天线的地板上,通过控制二极管开关的状态,可以实现左旋圆极化和线极化之间的切换,无需额外的偏置电路。利用仿真软件分析了CSRR 的尺寸和位置对天线圆极化特性的影响。所设计的天线工作在5. 8GHz 频段范围,测试结果与仿真结果吻合较好。实验结果表明,在圆极化状态下,中心频率5. 77GHz,-10dB 阻抗带宽约360MHz,最小轴比为1. 5dB,3dB 轴比带宽为80MHz;线极化状态下,中心频率5. 72GHz,-10dB 阻抗带宽约200MHz。天线增益均为6dB 左右,具有良好的方向性,可用于现代无线通信系统中。     

Design of Reconfigurable Millimeter-Wave Patch Antenna

Reconfigurable antenna is a novel concept of antenna. A novel reconfigurable millimeter-wave patch antenna is proposed and simulated by the finite-difference time-domain (FDTD) method. The simulation results demonstrate that the antenna can operate in two states and shift the operation frequency band between 22.8～30.8GHz and 28.7～37.3GHz as the state is changed. This antenna is useful for millimeter-wave wireless communication and radar systems.     

多约束条件下的阵列天线方向图可重构设计

介绍了一种多个约束条件下的阵列天线方向图可重构设计方法。在阵列激励功率种类与仅相位加权等条件的限制下,优化后的阵列天线多种方向图均满足了预设目标。首先,建立了多目标优化求解模型;然后,针对不同的问题采用了不同的优化方法进行求解。优化后的阵列采用了三种不同的功率组件,并在同一功率激励情况下采用不同的相位分布分别实现了低副瓣笔形波束、45°余割平方与22°扇形方向图的可重构设计,而且优化后的总输入功率较相同副瓣电平下的泰勒加权的总功率增加了约13%。     

A V-Band Beam-Steering Antenna on a Thin-Film Substrate With a Flip-Chip Interconnection

We propose a planar V-band beam-steering antenna based on a millimeter-wave (mm-wave) system-on-package technology using advanced thin-film technology on a silicon mother board. The thin-film substrate has the capability of integrated passive elements and flip-chip interconnection. Space-consuming components such as a microstrip Rotman lens and patch antennas are implemented on a low-loss, low-cost, and low-dielectric-constant material, benzocyclobutane. V-band monolithic microwave integrated circuits, a power amplifier, and a SP4T switch, are flip-chipped on the thin-film substrate while minimizing parasitic effects. The fabricated antenna module shows if-plane beam steering at four angles, plusmn6deg and plusmn20deg. The measured effective isotropic radiated power is in the range of 17.3-18 dBm. To our knowledge, this is the first demonstration of a planar mm-wave beam-steering antenna module on a thin-film substrate incorporating integrated terminating loads and flip-chip interconnections.     

Reconfigurable Multifunctional Ambipolar Polymer-Blend Transistors with Improved Switching-Off Capability

Ambipolar field-effect transistors allowing both holes and electrons transport can work in different states, which are attractive for simplifying the manufacture of circuits and endowing the circuits with reconfigurable multi-functionalities. However, conventional ambipolar transistors intrinsically suffer from poor switching-off capability because the gate electrode is not able to simultaneously deplete holes and electrons across the entire transport channel, which hurdles the practical applications. This study shows that the switching-off capability of polymer ambipolar transistor is significantly improved by up to three orders by introducing non-uniformly distributed compensation potentials along the channel to synchronically tune the charge transport at different channel locations. The non-uniform compensation potential is experimentally generated by the non-uniformly distributed electret charges, which are pre-injected into the insulators from source and drain electrodes. By this method, both n-type and p-type operations with high mobility (2.2 and 0.8 cm²s⁻¹V⁻¹ respectively) and high on/off ratio (10⁵) are obtained in the same device, and the different states are reversibly switchable. Moreover, this method endows the device with diverse device characteristics and reconfigurable multi-functionalities, which promotes the application of ambipolar transistors in complementary metal-oxide semiconductors-like circuits and some emerging electronics, including reconfigurable devices, multi-level memories, and artificial synapses.     

一种可重构超短波天线设计

介绍了一种超短波单鞭天线。通过使用可重构以及宽带匹配技术,与传统的套筒天线相比,大幅减小了天线的横向尺寸。仿真结果表明,该天线在工作频段内电压驻波比＜2,且具有良好的辐射特性。     

A Reconfigurable High-Gain Partially Reflecting Surface Antenna

A high-gain partially reflective surface (PRS) antenna with a reconfigurable operating frequency is presented. The operating frequency is electronically tuned by incorporating an array of phase agile reflection cells on a thin substrate above the ground plane of the resonator antenna, where the reflection phase of each cell is controlled by the bias voltage applied to a pair of varactor diodes. The new configuration enables continuous tuning of the antenna from 5.2 GHz to 5.95 GHz using commercially available varactor diodes, thus covering frequencies typically used for WLAN applications. Both the PRS and phase agile cell are analyzed, and theoretical and measured results for gain, tuning range, and radiation patterns of the reconfigurable antenna are described. The effect of the varactor diode series resistance on the performance of the antenna is also reported.      

一种对称型方向图可重构天线的设计

设计了一款对称型结构的方向图可重构天线,该天线可以工作在3.8GHz-6GHz频段.采用同轴馈电方式,辐射贴片通过开关S1、S2、S3和S4、S5、S6分别与左右两侧的寄生贴片相连.通过PIN二极管开关的"开"和"关"状态,辐射贴片给两侧的寄生贴片选择性的馈电,从而实现方向图可重构.天线在PIN二极管的控制下工作在两种模式下,在两种模式下频率、带宽特性相同,只有辐射方向图发生变化.本文利用HFSS软件对设计进行仿真分析,仿真结果表明,该天线在这两个频段内的回波损耗都小于-10dB,有较好的阻抗匹配特性.     

Reconfigurable Antenna for Future Wireless Communication Systems

This paper deals with the processing techniques which are known as reconfigurable antennas: these methods are foreseen to be a booster for the future high rate wireless communications, both for the benefits in terms of performance and for the capacity gains. In particular, adaptive digital signal processing can provide improved performance for the desired signal in terms of error probability or signal-to-noise ratio while the bandwidth efficiency can be increased linearly with the number of transmitting and receiving antennas. In this article, the main antenna processing techniques are reviewed and described, aiming at highlighting performance/complexity trade-offs and how they could be implemented in the future systems. The coexistence of all these different technologies in a wireless environment requires high efficiency and flexibility of the transceiver. Future transceiver implementations which are based on the Software Defined Radio technology are also reviewed and described.