Novel Double-Layer SIW Filter With Mechanically Adjustable Frequency Response

In this letter, a novel reconfigurable filter concept, which is called assembly reconfigurability through rotation, is proposed for the first time to implement a high-Q filter with adjustable frequency response. Two separated printed circuit boards (PCBs) are designed and assembled together to build a double-layer substrate integrated waveguide (SIW) filter. Guided by coupling matrix synthesis, the filter is designed to have adjustable filtering features by mechanically rotating one of the boards. Specifically, by only rotating the top PCB layer to different directions, three kinds of assembly states can be achieved, resulting in variable frequency response with transmission zeros (TZs) created at below, above, or both sides of the passband. Two design prototypes, which present 2- and 3-pole responses, respectively, are simulated and measured to validate the novel idea. The results show that two compact, low-loss fully shielded filters with adjustable response shape are developed, which well verify the concept of assembly reconfigurability for filter synthesis.