Study of finline-suspended stripline transitions for balanced MM wave mixers

• Main Author: Sia, Eng Kee.
• Other Authors: Fu, Jeffrey Shiang
• Format: Theses and Dissertations
• Published: 2008
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Antennas, wave guides, microwaves, radar, radio
• Online Access: http://hdl.handle.net/10356/3258
• Institution: Nanyang Technological University

Balanced mixer requires a hybrid to isolate Radio Frequency (RF) port from Local Oscillator (LO) port. In finline structure, this hybrid junction is replaced by simple finline to suspended substrate stripline transition. The transition used in the design is based on simplified circuit configuration that fulfils the requirement of better RF-LO isolation. In the LO port, the two fins of the antipodal finline are gradually tapered to a suspended substrate stripline end-coupled bandpass filter. It neglects the short and balun used in conventional finline to microstrip transition. In the RF port, a tapered finline is designed to match the mixer diode pair. The RF and LO ports are isolated from each other because the electric field lines in the finline and suspended substrate stripline are perpendicular to each other.