A compact Mobius ring bandpass filter embedded in low-temperature co-fired ceramics (LTCC) substrate

This paper newly proposes an LTCC-based Mobius ring bandpass filter, in which the Mobius ring is embedded in a microstrip line substrate so that the electromagnetic fields around a microstrip gap couple to the embedded Mobius ring smoothly. Simulated results indicate that a λ/4 resonance is occurred on the ring and the fields are confined within the Mobius ring. A prototype model is implemented by using an LTCC technology to confirm the theoretical predictions.