Reflective shunt diode RF amplitude modulator - has shunting diodes spaced so transmissive line sections have non-commensurate length

摘要

The transmission line length sections between diode pairs are selected so that a minimum in the frequency/attenuation curve resulting from one transmission line section/diode pair is cancelled by a maximum in the frequency/attenuation curve from another transmission line section/diode pair. The superposition of the frequency characteristics from all transmission line section/diode pairs results in a structure in which reactive cancellation occurs over the entire operating frequency range. - Consequently, it is not necessary to saturate the shunting diodes at the low band end to maintain maximum attenuation. In addition, to improve insertion loss, capacitive stubs are located along the transmission line which modify the filter characteristics when the shunting diodes are turned ''off''.