Wide‐band aperture array using a four‐channel manifold‐type planar multiplexer and digital 2‐D IIR filterbank

Emerging wide‐band communications and spectrum‐sensing systems demand support for multiple electronically scanned beams while maintaining a frequency independent, constant far‐field beam width. Realizing existing phased‐array technology on a digital scale is computationally intensive. Moreover, digitizing wide‐band signals at Nyquist rate requires complex high‐speed analog‐to‐digital converters (ADCs), which is challenging for real developments driven by the current ADC technology. A low‐complexity alternative proposed in this paper is the use of radio‐frequency (RF) channelizers for spectrum division followed by sub‐sampling of the RF sub‐bands, which results in extensive reduction of the necessary ADC operative frequency. The RF‐channelized array signals are directionally filtered using 2‐D digital filterbanks. This mixed‐domain RF/digital aperture array allows sub‐sampling, without utilizing multi‐rate 2‐D systolic arrays, which are difficult to realize in practice. Simulated examples showing 14–19 dB of rejection of wide‐band interference and noise for a processed bandwidth of 1.6 GHz are demonstrated. The sampling rate is 400 MHz. The proposed VLSI hardware uses a single‐phase clock signal of 400 MHz. Prototype hardware realizations and measurement using 65‐nm Xilinx field‐programmable gate arrays, as well as Cadence RTL synthesis results including gate counts, area‐time complexity, and dynamic power consumption for a 45‐nm CMOS circuit operating at B _DC = 1.1 V, are presented. Copyright © 2016 John Wiley & Sons, Ltd.     

改进的高精度功率放大器校准方法

针对当前无线通信系统中,功率放大器的校准效果是衡量一个系统好坏程度的重要指标,因而对功率放大器的校准具有重要作用。本文首先分析了射频模块的系统构成和控制机制,并对系统进行数理建模,将传统射频功率校准的问题转变成参数估值的问题。接着提出了精度和复杂度可控的基于能量守恒的最小均方(LMS)算法,该方法将变量的代数运算限制在一定的范围,而且不需要严格的限制输入数据的分布情况,这对于校准射频信号是极为有利的。仿真结果说明了所提出的算法能有效的将发射功率抑制在0.5dB范围内。     

集成滤波电感整流变压器的研究

本文中作者阐述了集成滤波电感整流变压器的原理,并通过一台300kVA样机的设计、制造和试验,验证了设计的正确性。     

一种射频功率检测控制系统的设计方法

介绍了一种宽频带射频功率检测控制系统的设计方法。采用2个支线形式的微带定向耦合器,耦合主通道不同频带的收发信号。通过CPU控制8个射频开关,实现收发信号切换、定向耦合器选择、以及收发信号分离滤波。收发信号的功率检测是通过定向耦合器将主通道的射频信号耦合到检波通道,经信号选择、滤波、放大后进入AD8362,转换为电压信号,然后经CPU的数模转换、查表补偿后上报功率。若检测到接收信号功率大于设置值,自动电平控制启动,CPU配置数控衰减器,将接收信号衰减到设置值以下,实现了收发通道射频信号功率检测上报、自动电平控制,以及多频段兼容。在实际工程设计中,为射频系统架构和电路设计人员,提供参考和依据。     

一种新型片上全差分电感的设计

提出了一种新型的片上全差分电感结构。电感采用全对称的几何形状,消除了传统差分电感因跳线引起的失配,提高了差分电感的性能。基于TSMC 0.18 μm RF CMOS工艺,对设计的全差分电感进行流片与测量,结果表明,差分电感两端口之间的失配量比传统差分电感下降了28%。     

基于 Fluent 的蒸汽喷射器结构研究与优化

设计了一种用于加热黏稠类物料的蒸汽喷射装置,基于计算流体力学软件 Fluent数值模拟方法对不同结构蒸汽喷射装置的速度场、温度场和压力场分布情况进行研究。结果表明,螺旋导柱截面宽度占据混合区域宽度约40％左右时,对蒸汽流的分散作用最佳,速度情况和出口温度分布情况较为理想;螺旋导柱截面形状为正方形时其压力和温度有最优解,为菱形时其湍动能分布有最优解。研究结果为改进蒸汽喷射器结构和提升喷射器的工作效率提供了必要的理论依据。     

Analog and radio-frequency performance analysis of silicon-nanotube MOSFETs

This work presents a comparative study of the influence of various parameters on the analog and RF properties of silicon-nanotube MOSFETs and nanowire-based gate-all-around (GAA) MOSFETs. The important analog and RF performance parameters of SiNT FETs and GAA MOSFETs, namely drain current (I_d), transconductance to drain current ratio (g_m/I_d), I_on/I_off, the cut-off frequency (f_T) and the maximum frequency of oscillation (f_MAX) are evaluated with the help of Y- and H-parameters which are obtained from a 3-D device simulator, ATLAS^TM. It is found that the silicon-nanotube MOSFETs have far more superior analog and RF characteristics (g_m/I_d, f_T and f_MAX) compared to the nanowire-based gate-all-around GAA MOSFETs. The silicon-nanotube MOSFET shows an improvement of~2.5 and 3 times in the case of f_T and f_MAX values respectively compared with the nanowire-based gate-all-around (GAA) MOSFET.     

RF Testing on a Mixed Signal Tester

In this paper, testing of radio frequency (RF) devices with mixed-signal testers is discussed. General purpose automatic test equipment (ATE) will be used. In this paper, a more universal test structure utilizing RF building blocks is proposed. A global positioning system (GPS) device is used as an example to illustrate how to develop the RF test plan with this usage. The test plan developed includes fast, cost-effective and dedicated circuitry.

2.45 GHz全集成CMOS功率放大器设计

在一个RF收发机系统中,功率放大器的集成问题一直是难点之一.首先简要介绍开关模式功率放大器及其提高效率的理论基础,然后采用0.18 μm CMOS工艺给出了工作在2.45 GHz的全集成单片功率放大器的设计,并采用ADS仿真软件验证了设计的正确性.     

集成电感设计优化方法

分析了已有电感结构,提出了一种独特的高性能的优化方案,使得螺旋电感的品质因数和差分特性都有了显著的提高.该优化设计尤其适合高性能全差分压控振荡器对高性能螺旋电感的需要.选取典型的单层正方形螺旋电感作为测试对象,工作频率2.439 GHz,芯片面积最大值限定为250 μm×250 μm,最小线间距为5 μm.