Receiver multicouplers - State of the art and optimum system design

The paper deals with circuit design techniques, performance of, and optimum system design with receiver multicouplers for HF through 800 MHz bands. Specifically, the design of receiver multicoupler amplifiers with the help of scattering (S-) parameters, feed-forward linearization technique, directional coupler/ transformer feedback are considered. Wideband power dividers made up of a cascade of standard two way ferrite power dividers or utilizing wideband transmission line ferrite/microstrip transformers are described. Pros and cons of each individual design technique in view of performance, cost and particular system application (frequency, bandwidth, ambient noise level etc.) are discussed. Typical values attained for the noise figure, intermodulation distortion, 3 dB de-sensization, output-to-output isolation, output-to-input isolation are given for each frequency band and/ or each design technique. Finally, relationships between the gain and noise figure of the receiver multicoupler and the receive system SINAD sensitivity are presented.