Passive varactor tuned equivalent transmission line phase shifter at C-band in 0.25 μ BiCMOS

The design of a C-band phase shifter fabricated in a commercial 0.25 mum BiCMOS technology is presented. Phase shift is enabled by tuning the varactors of a lumped element, equivalent of a transmission line. Only one single control voltage is required. The circuit is optimised for adaptive antenna combining on the basis of the 802.11a standard and matched for 50 Omega terminations. Within a frequency band ranging from 5.2 to 5.8 GHz, the circuit yields a phase control range of higher than 195deg, an insertion loss of only 3.6 +1.5 dB, return losses higher than 12 dB and a 1 dB compression point above 10 dBm. The chip and circuit areas amount to 0.6 and 0.25 mm², respectively. To the knowledge of the authors, at comparable phase control range, the lowest insertion loss for a passive phase shifter integrated in silicon reported to date is demonstrated.     

52 Gb/s 16:1 transmitter in 0.13 μm SiGe BiCMOS technology

A52-Gb/s 16:1 quarter-rate clocking transmitter for high-speed serial data transmission is designed to utilise 0.13-mum SiGe bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. The quarter-rate transmitter consists of a 16:1 multiplexer (MUX), a voltage-controlled ring oscillator, a phase-locked loop (PLL), a pseudorandom data generator and an output amplifier. The voltage-controlled ring oscillator has a wide tuning range from 11 to 22 GHz with feedforward loop and delay interpolation. A continuous model of a third-order PLL is developed and used to optimise loop filter parameters and to estimate the PLL performance in a simulation. The PLL achieves a low phase noise of -124.6 dBc/Hz at 1 MHz offset. The 16:1 MUX features quarter-rate clock multiplexing with multi-phase voltage-controlled oscillator clocks. In the design of a 16:1 MUX, an edge-channelling 4:1 MUX is used to alleviate a duty cycle and a jitter problem.     

A cost-effective technique for extending the low-frequency range ofa microwave noise parameter test set

The operating frequency range of an on-wafer noise parameter test set based on the multiple-impedance technique has been extended in the low-microwave frequency range (down to the L-band). A simple technique, using a phase shifter cascaded with the microwave tuner, allows different reflection coefficients of the load impedance to be obtained at the device input. These coefficients are well distributed over the Smith chart in the entire frequency range. As an example, noise parameters of a passive device have been measured between 1 and 8 GHz, and a good agreement between measured and calculated values is observed. This technique has also been used to measure the noise parameters of different heterojunction bipolar transistors. A minimum noise figure of 1 dB was obtained at 1 GHz on a GaAlAs/GaAs HBT which is in agreement with expected results     

Broad tuning ultra low phase noise dielectric resonator oscillators using SiGe amplifier and ceramic-based resonators

This paper describes the design of very low noise, tunable, X-band dielectric resonator oscillators (DROs) demonstrating phase-noise performance of -135 dBc/Hz at 10 kHz offset. SiGe transistors are used for the oscillator sustaining amplifiers that offer a circulating power of 12 dBm and a gain of 5.4 dB per stage as well as a low flicker noise corner of 40 kHz. A variety of resonator configurations utilising BaTiO₃ resonators are presented demonstrating unloaded Qs from 10 000 to 22 000. These resonators are optimised and coupled to the amplifiers for minimum phase noise where Q_L/Q₀ = 1/2, and hence S₂₁ = -6 dB. To incorporate tuning with low additional phase noise, a phase shifter is also investigated. The theory for the low noise oscillator design is included; experimental results demonstrate close correlation with the theory.     

Novel and Simple High-Frequency Single-Port Vector Network Analyzer

Portable, accurate, and relatively inexpensive highfrequency vector network analyzers (VNAs) have great utility for a wide range of applications, encompassing microwave circuit characterization, reflectometry, imaging, material characterization, and nondestructive testing to name a few. To meet the rising demand for VNAs possessing the aforementioned attributes, we present a novel and simple VNA design based on a standing-wave probing device and an electronically controllable phase shifter. The phase shifter is inserted between a device under test (DUT) and a standing-wave probing device. The complex reflection coefficient of the DUT is then obtained from multiple standing-wave voltage measurements taken for several different values of the phase shift. The proposed VNA design eliminates the need for expensive heterodyne detection schemes required for tunedreceiver-based VNA designs. Compared with previously developed VNAs that operate based on performing multiple power measurements, the proposed VNA utilizes a single power detector without the need for multiport hybrid couplers. In this paper, the efficacy of the proposed VNA is demonstrated via numerical simulations and experimental measurements. For this purpose, measurements of various DUTs obtained using an X-band (8.2–12.4 GHz) prototype VNA are presented and compared with results obtained using an Agilent HP8510C VNA. The results show that the proposed VNA provides highly accurate vector measurements with typical errors on the order of 0.02 and 1$^{circ}$ for magnitude and phase, respectively.      

Silicon germanium programmable circuits for gigahertz applications

Implementation of a silicon germanium (SiGe) field programmable gate array (FPGA) has been described. The reconfigurable basic cell (BC) that evolved from the Xilinx XC6200 has been redesigned to achieve high speed with lower power consumption. The propagation delay of the BC in comparison to the BC implemented in the earlier generation SiGe process has been reduced to 18% of its original value (from 240 to 42 ps) and the power consumption has been comparably reduced. The range of power reduction is from 13% of its original value when the BC is fully turned on down to 2% when the power saving scheme is applied. A 20times20 SiGe FPGA with physical dimensions of 4.5times4.8 mm has been fabricated using the IBM 120 GHz (7HP) process. To deliver a 10 GHz clock, an H tree has been designed and implemented with reduced skew. To demonstrate its performance, a 4:1 multiplexer (MUX) has been mapped for comparison with various CMOS FPGAs. The SiGe FPGA can achieve an 8 Gbps transmission rate, which is a 40 times improvement over the same implementation on a Xilinx Virtex CMOS FPGA. Other comparisons between the SiGe FPGA and commercial FPGAs have also been included. From simulations and measurements, the SiGe FPGAs have been shown to have high performance that can successfully tackle gigahertz applications     

A finline 60-GHz phase shifter based on a (Ba,Sr)TiO3 ferroelectric thin film

The design and microwave characteristics of a ferroelectric thin film slotline-waveguide phase shifter operating in the millimeter wavelength range (f～60 GHz) are presented. In this frequency range, the phase shifter possesses a figure of merit F=32 deg/dB and provides for a continuous phase shift in the interval from zero to 255 deg. The ferroelectric films are characterized by a dielectric loss tangent of tan δ=0.04 at a tunability factor of K≈1.7, which are promising parameters for the given frequency range.     

基于高电阻率衬底的Si/SiGe HBT

介绍了一种基于电阻率高达1000Ω·cm的硅衬底的锗硅异质结晶体管的研制.首先根据衬底寄生参数模型分析了衬底对器件高频性能的影响,然后设计了器件的材料与横向结构尺寸,该器件采用掩埋金属自对准技术在3μm工艺线上制备而成,测得其典型直流电流增益为120,BVCEO为9.0V,fT为10.2GHz,fmax为5.3GHz,比同结构尺寸的常规N 衬底Si/SiGe HBT的fT和fmax分别高出3.9GHz和1.5GHz.     

Microstrip delay line phase shifter by actuating integrated ground plane membranes

The design, simulation, fabrication, measurement and performance of a V-band micro- strip delay line phase shifter using electrostatically actuated integrated micro-machined ground plane membranes are presented. The microstrip line is etched on an RFIC-friendly silicon substrate. The membrane is made of aluminium micro-ribbons and is fabricated on the ground plane side of the silicon substrate. The actuation of the ribbons away from the transmission line introduces an air gap between the radio-frequency (RF) substrate and the ground plane. By controlling the air gap thickness, a controllable phase shift in the transmission line is obtained. Each micro-ribbon measures 3.20 mm in length, 20 mum in width and 1 mum in thickness. A measured phase shift of 41deg at 50 GHz was achieved with an actuation voltage of 120 V. The fabrication process added a 20 mum initial air gap between the micro-ribbons and RF substrate, increasing the required actuation voltage for a given phase shift. The simulated phase shift results agree well with the measurements.     

A microwave cryogenic low-noise amplifier based on sige heterostructures

A low-noise cryogenic amplifier for the measurement of weak microwave signals at sub-Kelvin temperatures is constructed. The amplifier has five stages based on SiGe bipolar heterostructure transistors and has a gain factor of 35 dB in the frequency band from 100 MHz to 4 GHz at an operating temperature of 800 mK. The parameters of a superconducting quantum bit measured with this amplifier in the ultralow-power mode are presented as an application example. The amplitude–frequency response of the “supercon-ducting qubit–coplanar cavity” structure is demonstrated. The ground state of the qubit is characterized in the quasi-dispersive measurement mode.     

Microwave phase shifter with planar capacitors using strontium titanate films

A design of a microwave phase shifter based on a loaded microstrip line using planar SrTiO₃ capacitors as nonlinear elements is described. The microwave phase shifter (at T=300 K) demonstrated a continuous phase shift between 0 and ∼55 deg in the frequency range 8.6–9.0 GHz with a phase error not exceeding 5 deg. The quality parameter of the phase shifter in the operating frequency range was 110 deg/dB. Pis’ma Zh. Tekh. Fiz. 25, 78–83 (October 26, 1999)     

Mesa and planar SiGe-HBTs on MBE-wafers

SiGe-HBTs have the potential for outstanding analog and digital or mixed-signal high frequency circuits widely based on standard Si technology. Here we review on MBE grown transistors and circuits. Processes and results of a research-like SiGe HBT and two possible production relevant HBT versions are presented. The high frequency results with f_max and f_T up to 120 GHz and a minimum noise figure of 0.9 dB at 10 GHz demonstrate the advantage of using MBE samples with steep and high base doping and high germanium contents. A comparison to the concept of reported low doped, low germanium and triangular profiled SiGe base layers, realized by UHV-CVD, is given. In addition, some circuit demonstrators of SiGe-ICs will be presented.     

SiGe-based FETs: buffer issues and device results

SiGe quantum well structures gain increasing interest in the Si technology. The preparation of a Si channel or a Ge-rich or even a pure Ge channel with a respective two-dimensional carrier gas opens the attractive possibility to fabricate high performance n- or p-type field effect transistors. For both device types, a virtual substrate surface is required which is created by a strain relieved buffer layer grown on a Si standard wafer. The paper reviews various approaches of SiGe buffers including special attempts to reduce the thickness and to improve the quality. N- and p-type modulation-doped field-effect transistors are presented which show comparably good device characteristics and cut-off frequencies in the range of 100–120 GHz.     

Interface for MEMS-based rotational accelerometer for HDD applications with 2.5 rad/s/sup 2/ resolution and digital output

A 0.6 /spl mu/m BiCMOS interface for microelectromechanical systems (MEMS) based rotational accelerometers is presented. It is housed in an inexpensive standard SO-24 plastic package with a capacitive rotational accelerometer sensor produced using MEMS technology. This sensitive interface chip includes the analog-to-digital conversion, filtering, and interface functions. The analog-to-digital conversion is realized through a single-bit electromechanical /spl Sigma/-/spl Delta/ loop able to detect capacitive unbalancing as low as 50 aF (50/spl times/10/sup -18/ F). The produced bitstream is then processed by a digital chain and made available through a standard 3.3 V (5 V tolerant) three-wire serial bus. The signal bandwidth is about 800 Hz, the sensitivity is 2.5 rad/s/sup 2/, with a full-scale sinewave of 200 rad/s/sup 2/ and a signal-to-noise ratio peak of 38 dB over 30-800 Hz. Through the serial bus, it is also possible to program device characteristics including gain, offset, filter performance, and phase delay. The complete sensor is used in a feed-forward compensation scheme to cancel external disturbances acting on computer hard-disk drives so as to steadily keep the read-write heads on track: this allows greater track densities and better speed performance.     

一种新颖的共享一个兰格耦合器的22.5°和11.25°MMIC多倍频程移相器

介绍了一种新颖的在5～20GHz频率范围的共享一个兰格耦合器的22.5°和11.25°MMIC多倍频程移相器的设计、制造和性能.选择了工艺变化对电路性能最小的电路拓扑.在5～20GHz频率范围内,以展示出低的峰值相移误差(≤2°);低的输入/输出驻波(≤1.5)和低插入损耗及起伏(≤(2.6±0.4)dB).芯片尺寸为:4.2mm×0.46mm×0.1mm.     

Design and implementation of a substrate integrated waveguide phase shifter

The design and implementation of a phase shifter based on the substrate integrated waveguide (SIW) technique operating at 10 GHz are presented. The proposed phase shifter consists of a SIW section with two inserted metallic posts. The phase shifting in this configuration is achieved by changing the diameter and the position of these posts. Numerical simulations have been carried out for different diameters and positions, which have shown good agreement with the theory. A parametric study was also conducted to assess the impact of errors made on the diameter and position of the two metallic posts. To prove the concept, prototypes were fabricated and measured. Experimental results agree well with simulations and SII was better than -14 dB, S21 better than -1.08 dB and the phase error was less than 1.5deg.     

Wi-Fi/WiMAX双极化阵列天线研究

提出一种应用于Wi-Fi/WiMAX的宽带高增益双极化阵列天线.它由+45°和-45°正交极化的两个天线组成。当频率为2.38~2.72 GHz时,天线的回波损耗大于-10 dB;端口1与端口2之间隔离度大于20 dB;端口1在2.45 GHz时获得最大增益为17.14 dBi,端口2在2.483 GHz时获得最大增益为17.15 dBi.仿真和测试很好相吻合,该双极化天线能满足Wi-Fi/WiMAX通信网络要求.     

Millimetre-wave monopulse antenna incorporating substrate integrated waveguide phase shifter

A compact planar E-plane monopulse antenna is proposed and realised at 36.5 GHz for millimetre-wave radar or direction-finding system application, which is built on the substrate integrated waveguide (SIW) technology. A phase shifter having a non-uniform SIW width configuration is self-consistently made of a periodically embedded via array and it can achieve good performances over a relative broad bandwidth. A 180deg directional coupler incorporating this proposed phase shifter structure is developed in the design of an integrated feeding network for the monopulse antenna. Four elements array based on the configuration of antipodal linearly tapered slot antenna is designed as radiator, offering a pair of 'sum' and 'difference' beams along the long direction of the substrate. Measured gain of the 'sum' beam is higher than 16 dBi, whereas the zero depth of the 'difference' beam is lower than -38 dB. This type of monopulse antenna presents an excellent candidate in the development of intelligent millimetre-wave directional- finding system.     

Nonlinear microwave spin wave interferometer

The characteristics of a nonlinear microwave spin wave interferometer were experimentally studied for the first time. The interferometer was implemented according to a bridge scheme with a nonlinear spin wave phase shifter based on an yttrium-iron garnet film. The maximum sensitivity of the nonlinear interferometer with respect to the input signal level was reached with a phase shifter operating on the forward volume spin waves. In the GHz frequency range, an increase in the microwave power up to a few mW led to a signal phase shift exceeding 180 °.     

A transceiver system for dual‐simplex high‐bit‐rate digital subscriber lines

Abstract

High bit‐rate digital subscriber lines (HDSL) technology is a new technology that may provide bi‐directional transmission at a rate of 1.544 Mb/s in conventional copper wires. A transceiver system for dual‐simplex (DSX)‐HDSL is presented. Simulation results show that the DSX‐HDSL system combined with simple pair‐selection can provide 18Kft/24AWG service distance without line repeaters. In the presented DSX‐HDSL transceiver, 2B1Q code with (1‐D) precoding is used to reduce the inter‐symbol interference (ISI) and the dynamic range of signal. Hence, a 12‐bit or less A/D converter can satisfy the performance requirement. In addition, another switchable (1‐D) filter is used in the receiver to shorten the duration of channel response, therefore a (5, 32) hybrid‐decision‐feedback‐equalizer (DFE) can obtain an adequate performance.