Novel Design Concept for Microstrip Dual Band Bandpass Filter by Using Patch Loaded Resonator and Short-Circuited Stub

Microstrip dual band bandpass filters using the capacitively loaded patch and short-circuited stub is presented. The proposed topology is occurred by adding short-circuited stub in the center of a main transmission line and square patches on both sides of the stub in two different forms. The bandwidth and modes of the both passbands are controlled by adjusting the parameters associated with the stub and patch, appropriately. Two different paths are used between the input and output ports to obtain two different filtering characteristics. The proposed circuits are fabricated and measured to demonstrate the experimental verification. The measured and simulated results exhibit good agreement.