Radiophysics faculty, Saint-Petersburg Polytechnic University, 29 Polytekhnicheskaya st., 195251, Saint-Petersburg, Russia

Abstract – A nonlinear FET model, including approximating voltage dependencies of drain current, gate–source capacitance and resistance is considered. The technique based on the harmonic balance for the calculation of stationary oscillation is described. A new parametric synthesis method of microwave oscillator with “star-like” structure is proposed. This method enables to get automatically necessary frequency and power. The PC program for the design of integrated microwave FET oscillators is described.

Dept. of Microelectronics & Radio Engineering, St. Petersburg Electrotechnical University, 5 Prof. Popov st., 197376, St. Petersburg, Russia

Introduction
Microwave components for gain settings and control function have applications in a number of areas. Such the components are used in multichannel communication systems where the gains through different channels need equalization. Digitally controlled attenuators are also required for phased array antennas, 'smart' antennas and other similar applications. Design of a digital 5-bit GaAs MMIC attenuator with the operating frequency band of 8-12 GHz is presented in this paper. The attenuator consists of cascaded units of individual bit, which can be switched on or off to provide the desired value of attenuation from 0.75 dB to23.25 dB with the step of 0.75 dB.

Dept. of Microelectronics & Radio Engineering, St.-Petersburg Electrotechnical University, 5, Prof. Popov Str., St.-Petersburg 197376 Russia.

Abstract – An original design of a microwave wideband filter is presented. The filter is composed of parallel-coupled microstrip resonators on the top side of dielectric substrate and an aperture on the bottom side. The filter with the central frequency of 2.1 GHz and the  fractional bandwidth 40% has been designed.

Dept. of Microelectronics & Radio Engineering, St. Petersburg Electrotechnical University, 5 Prof. Popov St., 197376, St. Petersburg, Russia

Abstract – The paper presents the three-pole microstrip bandpass filter without second spurious passband, which was suppressed by additional capacitors placed between resonators. The filter layout and simulation results are presented and discussed.

¹⁾ United Microwave Laboratory, Saint Petersburg Electrotechnical University, 5 Prof. Popov str.,
 St. Petersburg, 197376, Russia
²⁾ Centre for Physical Electronics and Materials, London South Bank University, 103 Borough Road, London SE1 0AA, UK

Abstract – A frequency tunable microwave filter based on a dual mode dielectric resonator has been developed. Tuning of the filter was realized by using metal plate located over the dielectric resonator and moved along the resonator axis by a piezoelectric bimorph. The main parameters of the filter are the following: central frequency of the tuning range 2.35 GHz, bandwidth for 1dB level 0.5%, tuning range about 10%, the insertion loss less then 1dB.