Broadband Detection Logarithmic Study Video Amplifier

Detector Logarithmic Video Amplifiers (DLVAs) are the key components in measuring high speed microwave pulses. The advantage of DLVAs is relatively simple structure, easy realization and can work in an extremely working bandwith. This paper mainly foucus on the design and the realization of a18-40GHz DLVAs.The most common microwave receiver types and their characteristics are discussed and compared in the first chapter.The detail block diagram of the DLVAs and their characters are gave in Charpter two. The parameters and terms to specify the DLVAs are presented. The constraints that can influence the perfomance are discuse and solutions are present.Chapter three mainly foucus on designing of a broadband microwave detector.The principle of the microwave limiters and the common approach in designing the microwave limiters are discussed in the fourth charpter. Schottky diode and PIN diode in microwave limiters design application are compared in the chapter, test results based on experiments gave respectively. A schottky diode microwave limiter has working frequency from18GHz to40GHz is presented.A DLVA has a working frequency18-40GHz designed in the final charpter, microwave part and video circuit part of the DLVA were discussed in detail respectively. The DLVA is compact. The Tangential Signal Sensitivity (TSS) of the DLVA decreased as the frequency rised, TSS is-40dBm in40GHz, dynamic range is42dB, DC offcet is900mV, Log linearity is within±8dB.