Aung Bo Bo Hein, V.A. Romanyuk

The procedure of millimeter wave amplifier electrical circuit design is described. An amplifier should be made as MMIC based on HEMT field effect transistor. The design carries out in the nonlinear regime of the Microwave Office program. Angelov 2 uses as a model of the transistor. The first stage determines the optimal mode of transistor operation. The maximum power gain is the optimality criterion. For this purpose the optimum bias voltage to the gate of the transistor is determined and the input and output impedances of the transistor are calculated. Thereafter the value of circuit reactive elements, compensating the imaginary parts of impedances, are determined. In order to check whether the transistor voltages does not exceed the allowable values, depending on the time instant voltages of the transistor were calculated. In the second stage the following networks: input and output matching circuits and the circuit of self-bias - are calculated. The simple LC elements of the network Г-shaped form are the matching circuits in the narrow-band amplifiers. Matching circuits transform the real parts of the impedance of the transistor in the resistance of 50 ohms. As a result of the second stage the electrical circuit of the amplifier is known. In the designed circuit amplifier its basic characteristics and parameters - frequency response and range of output fluctuations are calculated. This design procedure is demonstrated by the example of the power amplifier of the oscillation frequency of 35 GHz with an input power of 8...12 dBm, the specified maximum allowable electrical parameters of the transistor and the limited size of the monolithic circuit.