A Novel MillimeterWave Rectangular WaveguideMicrostrip Transition Based on the Principle of Magnetic Field Coupling

A novel circuit construction of rectangular waveguidemicrostrip transition based on the principle of magnetic field coupling in rectangular waveguide is proposed in the paper. The circuit construction is composed of a ring metal strip on microstrip substrate placed in the E plane of rectangular waveguide, and a section of decentre coaxialline partial filled medium. Inside and outside conductors of the coaxialline are all rectangular. The circuit construction achieves a good conversion of master modes from rectangular waveguide to microstrip. It has the advantages of low insertion loss, wide frequency band, compact structure and avoiding debug, etc. The transition circuit is designed and simulated at Ka band by using CST simulation software .The measured results show the insertion loss of the backtoback transition is less than 1.2 dB and the return loss is better than -15dB in the frequency range of 29~40GHz.