MICROWAVE TRANSISTOR MOUNT

PURPOSE:To obtain an element configuration without low frequency oscillations by a method wherein a high impedance microstrip line is led from a part of a microstrip line having a characteristic impedance of 50OMEGA and which is formed on a substrate such as alumina ceramic or the like, and with a capacitor and a resistor connected to it. CONSTITUTION:An alumina ceramic substrate 2 is mounted in a brass chamber 1, and a microstrip line 3 is formed on the substrate, and in the middle of this substrate is placed a microwave transistor 4, and each electrode terminal is connected to the chamber 1 and the line 3. Subsequently from bias stays 5 provided at both outsides of the configuration a bias voltage and an RF signal are applied to the transistor 4 and the characteristics of the transistor 4 for microwave is measured. And for the puroose of setting the impedance of the measuring system to be 50OMEGA, the relation between the width W of the line 3 and the thickness t is taken to be W=t. In this constitution a high impedance line 6 is led from the middle of the line 3, and by capacitor 7 and a resistor connected at its tip, the low frequency oscillation is suppressed.