A Wideband Microwave Power Divider/Combiner with Multiple-Port Double-Ladder Structure

We propose a new microwave power divider/combiner with multiple-port doubleladder structure for use in high power solid-state power amplifiers. Numerical and experimental analysis were carried out at X-band, and the results of the divider/combiner indicated low insertion loss and wide band characteristics in good accordance with the theory

An x-band RFIC active phase shifter

Abstract— An active RFIC X-band phase shifter is implemented using IHP SiGe HBT 0.25 μm SGB25V technology with an improved vector sum method. The chip is formed by a three way Wilkinson power divider, three phase delays for 0-120-240 degrees, three similar RFIC LNAs and a final three way Wilkinson power combiner on the same chip and occupies an area of 4x1.8 mm2. The circuit provides both phase and amplitude control without the need of any additional digital circuitry. Phase shifting is simply based on the weighted vector sum of three vectors which are separated by 120º from each other. All 0-360 degree phase can be scanned simply by this method with the addition of amplitude control. The RFIC LNA circuit is fabricated and measurement results show that LNA has a gain of 10 - 13 dB with in the band of 6-9 GHz and 2-3 dB NF within the same band. The simulation results show that the phase can be scanned from 0-360 degrees with average 7 degree resolution for a 2 dB amplifier gain change. The gain of the overall active phase shifter circuit is 12-13 dB with output gain flatness is 1 dB and the circuit consumes 15.36 mW power. The circuit combines the amplifier with phase shifter and can be used for X-band applications

A 1-W, 30-ghz, CPW Amplifier for ACTS Small Terminal Uplink

The progress is described of the development of a 1 W, 30 GHz, coplanar waveguide (CPW) amplifier for the Advanced Communication Technology Satellite (ACTS)Small Terminal Uplink. The amplifier is based on Texas Instruments' monolithic microwave integrated circuit (MMIC) amplifiers; a three stage, low power amplifier, and a single stage, high power amplifier. The amplifiers have a power output of 190 mW and 0.710 W, gain of 23 and 4.2 dB, and efficiencies of 30.2 and 24 percent for the three stage and one stage amplifiers, respectively. The chips are to be combined via a CPW power divider/combiner circuit to yield the desired 1 W of output power

Ultra wideband tapered power combiner/divider

Cataloged from PDF version of article.Many typologies like the designs of Wilkinson Power Divider and Gysel Power Divider have been worked and improved through the years. Each design targets a higher bandwidth, a better isolation and a higher power handling capacity or smaller size. The basic analysis of every structure begins with the even mode and the odd mode models. The tapered lines are ultra wideband matching structures that are used to match real impedances. The only limitation of tapered line is the size, which has to be the half wavelength of the lower frequency limit. The tapered lines do not have any upper frequency cut-off. Because of the limitations in sizes, tapered lines have not been able to be used very commonly. The proposed new topology has a new taper topology with a single capacitor at the input side to decrease the lower frequency limit of the tapered line. The even mode structure of the proposed power divider/combiner is constructed of these improved tapered lines. In the odd mode analysis, the N section Wilkinson power divider/combiner design has been used. In order to determine the isolation resistor values, four different methods have been proposed. The proposed structure uses the surface resistive materials to implement these resistors. It has been observed that continuity of the isolation resistors between transmission lines causes some loss in the even mode. In order to solve this problem, the width of the resistors should be as small as possible to prevent the even mode loss.Ünlü, OkanM.S

A high gain antenna system for airborne satellite communication applications

A high gain antenna for commercial aviation satellites communication is discussed. Electromagnetic and practical design considerations as well as candidate systems implementation are presented. An evaluation of these implementation schemes is given, resulting in the selection of a simple top mounted aerodynamic phased array antenna with a remotely located beam steering unit. This concept has been developed into a popular product known as the Canadian Marconi Company CMA-2100. A description of the technical details is followed by a summary of results from the first production antennas

A waveguide type power divider/combiner of double-ladder multiple-port structure

We propose a waveguide type microwave power divider/combiner of double ladder multiport structure which is advantageous for its very low insertion loss and high power capability. Analysis based on equivalent circuits give the design formula for perfect power dividing/combining. Numerical analysis gives optimal design parameters for broadband characteristics both of the divider and of the combiner. Analyses of power flows in the divider structure and isolation characteristic are given. Operation characteristics of divider-combiner system and the effect of phase deviation in combiner input signals on the combining efficiency are also discussed. Experiments showed good performances in accordance with the theory: the -0.5 dB relative bandwidths of four-, eight-, and twelve-way deciders were as large as 0.5, 0.38, and 0.38 respectively. For four- and eight-way divider-combiner systems, relative bandwidths were 0.22 and 0.13, respectively both with insertion loss of less than 0.1 d

Full-band oversized turnstile-based waveguide four-way power divider/combiner for high-power applications

Very high-power and high-efficiency microwave applications require waveguide structures to combine/divide the power from/to a variable number of high-power solid-state devices. In the literature, among the different waveguide configurations, those capable of providing the maximum output power show a limited relative bandwidth. To overcome this limitation, in this paper a full-band (40%) waveguide power divider/combiner specifically designed for high-power applications (up to several kW) is presented. The proposed structure uses an evolved turnstile junction with a standard rectangular waveguide common port, rotated 45°, with respect to its central axis, to divide/combine the signal to/from the four output/input rectangular ports. The inclusion of an oversized central cavity together with circular and rectangular waveguide impedance transformers at the common port allows the achievement of a full-band operation with excellent electrical performance, while maintaining a very simple and compact configuration. Only two layers of metal are required for the physical implementation of this structure in platelet configuration. A prototype has been designed covering the full Ka-band (26.5-40 GHz), showing an excellent measured performance with around 30 dB of return loss, 0.18 dB of insertion loss, and less than 1.5° of phase imbalance

Measurement and Evaluation of Tx/ Rx Antennas for X-Band Radar System

This paper presents the performance evaluation of antennas for microwave transmission and reception in X-band radar systems. The transmitter (Tx) and receiver (Rx) antennas are fabricated on microstrip array structures. The antennas are connected to microwave circuits with transmission lines, coaxial cables, and microwave combiners and splitters. The designed antennas in X-band microwave operation for Tx and Rx parts were fabricated identically by 4x64 microstrip patch antennasin an array structure. The fabricated antennas were measured for return loss (S11), VSWR, radiation pattern, and Gain. The detail methods for the measurements are reported and their results are also discussed. The measured antenna gain of ~20dBi, and beam-width of ~20degreecan be obtained using the fabricated antennas at 9.4GHz microwave operation