In The Microwave Communications Repeater Diplexer / Low Noise Amplifier Module Design

The duplexer/LNA module presented here is an essential part of wireless communication repeater system. The module enjoys such merits: narrow bandwidth, low insertion loss in the pass band, high attenuation in the stop band, low noise figure and high gain. Besides, its structure is compact and easy to be manufactured. The introduced module is used at the RF-front of repeater system and used to share common antenna system for both uplink and downlink signal with perfect isolation. The LNA part can provide low-noise and high-gain performance which is helpful for receiver sensitivity and consequent noise suppression. Meanwhile, the integrated module must have higher performance-price rate compared with individual components.During the course of research, focuses are put on three main points. On the basis of theories of coupling cavity filter design, we study the approaching method of this kind of filter in engineering and offered design process with test curve. After that, we go through main performance factors of low-noise amplifier according to two-port microwave network theory, also with design process and test result followed. The emphasis is to select appropriate amplifier component to achieve specific performance. This paper here makes use of E-PHEMT to gain enough low noise figure with appropriate gain and stability. Finally, we unite duplexer and LNA to become a compact module, analysis of possible issue in engineering is made to guide further improvement. Seen from final module test curve, requirement from customer can be met.