A New Class of Wideband MS-to-MS Vialess Vertical Transition with Function of Filtering Performance

A new class of wideband microstrip (MS)-to-microstrip (MS) vialess vertical transition with function of filtering performance is proposed and demonstrated on coplanar waveguide (CPW) resonator in this paper. Initially, a higher unloaded quality factor (Qu) in the proposed CPW resonator than a conventional slotline resonator shows that the CPW resonator is a better choice for design of the proposed transition than its counterpart on slotline resonator. Meanwhile, to give an insight into the Qu of the CPW resonator, the underlying working mechanism how the proposed CPW resonator is provided with higher Qu than the slotline resonator is elaborated. Then, resonant mode in the proposed CPW resonator will be properly investigated. After that, to facilitate design process, a synthesis design method is introduced for design of the proposed transition. Finally, one design example, i.e., a three-pole vertical transition, is designed, constructed, and experimentally verified. The three sets of results, i.e., expected, simulated and measured results of the proposed transition match well with each other.