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 brief. Initially, a higher unloaded quality factor (<inline-formula> <tex-math notation="LaTeX">${Q} _{u}$ </tex-math></inline-formula>) 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 <inline-formula> <tex-math notation="LaTeX">${Q} _{u}$ </tex-math></inline-formula> of the CPW resonator, the underlying working mechanism how the proposed CPW resonator is provided with higher <inline-formula> <tex-math notation="LaTeX">${Q} _{u}$ </tex-math></inline-formula> 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.