We present a novel UMTS diplexer design using the filters of antiparallel-coupled lines structure loaded with a stepped impedance microstrip resonator. The diplexer is composed of two filters. And a microstrip line of quarter-wavelength is used to links each filter to the common port. The composing filters exhibit two tunable transmission zeros which are used to implement the mid-passband zero implantation for improving the isolation between the transmitting (Tx) and the receiving (Rx) ports. A pair of spurlines is used in the coupled lines of the Tx-filter to further increase the isolation. An experiment is conducted to assure the diplexer's performance and to verify the circuit design.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Electrical and Electronic Engineering