Abstract:Common collector common base cascaded transistor structure can compose limiting amplifiers because of special IV curve between the emitter junctions. The first transistor is common collector and the second transistor is common base so that the amplifier can limit the output wave to non-saturation, which means limiting the output power. Because both of the common collector and common base transistors have broadband structures, the final amplifiers are of broadband characteristic. A broadband limiting amplifier is designed, which operates from 10 MHz to 200 MHz, with the gain of 25 dB, the limiting power of 2 dBm, the return loss upper 20 dB. A compact limiting amplifier is designed by thin film circuit technology, whose size is 7.15 mm×8.1 mm, smaller than that by traditional Printed Circuit Board (PCB) technology. The limiting amplifier has smaller size and more excellent performance.