Multilayered U-shape diplexer for high performance multifunctional wireless communication systems

This article proposes a design technique of high performance diplexer for multi-wireless networks based on multilayered u-shape resonators. In this technique, the desired passband of each filter is analysed and constructed using two substrates. On the bottom substrate, two u-shape resonators are designed and electrically coupled to specify and control the desired passband. To obtain the filtering response of the designed filter, a grounded input/output u-shape transmission line is patterned on a top substrate and vertically integrated with the bottom substrate. Indeed, two filters are realized and cascaded to perform the desired diplexer. As a result, a compact diplexer with fully independent elliptical behaviour passbands can be achieved. To verify the proposed technique, a (2.4 GHz WLAN/ 3.5 GHz WiMax) diplexer with a compact size of 23.8 mm x 11.5 mm is designed, simulated, and tested. The measurement responses are very well following the simulation results.