The Design of Frequency-tunable Mechanical Tuning Coupler Based on Coupled Line Structure

In the current study, a frequency-tunable mechanical tuning coupler based on coupled line structure is proposed, which shall have high stability and high flexibility of tuning. This mechanical tuning coupler is based on coupled line structure of microstrip technology. This coupler is composed by baseplate for signal transmission and mobile plate for mechanical tuning. By mechanically tuning the rotation angle, the coupling length is changed and tunability is achieved. The operating frequency can be tuned from 1.02GHz to 1.27GHz while the rotation angle is tuned from 180° to 135° approximately. The design principle is based on quarter-wave resonance phenomenon of coupled line.