Compact and Broadband Microstrip Line-to- Rectangular Waveguide Transition Using Magnetic Coupling Resonator and Ground Resonators

In this article, a compact and broadband microstrip line-to-rectangular waveguide (MSL-to-RWG) transition using the magnetic coupling resonator and ground resonators is proposed. The circuit size of the transition occupies only one-eighth of the guided wavelength, while the fractional bandwidth of the transition is 42.7%, which covers the frequency range from 8.2 to 12.6 GHz, encompassing the whole frequency range of the X-band (8.2–12.4 GHz). In this frequency range, the reflection coefficient is smaller than −15 dB, while the transmission coefficient is larger than −0.18 dB. In order to verify the simulation results, the MSL-to-RWG transition is fabricated and measured where the measurement results are in reasonable agreement with the simulation results.