A Multilayer Ultra-Wideband Directional Coupler

Abstract

Inthis contribution, the well-known vertically installed planar coupler is introduced briefly,and an improved assembly technique is proposed increasing the mechanical stability of the coupler.Then, the design of anovel multilayer planar,ultra-wideband, five-sectional 3dBdirectional couplerwith an easier fabrication process and lower heightispresented. In this approach, the necessary tight coupling at the center section for the desired ultra-broadband behavior is achieved with amultilayer configuration insteadofa vertically installed substrate. The manufactured multilayer couplerhas acoupling and insertionloss of 3.4 dB AE 1.1 dB and an isolation and return loss of better than 14 dB in the operating bandwidth between 3.1 -10.6 GHz. The designprocedure, identical for both coupler types, needs no time-consuming full-wave analysis and will be describedindetail for the novel multilayer coupler.

Planar Directional Couplers and Filters

“…To overcome the tendency of forward wave coupling present in waveguides with inhomogeneous cross sections, wiggly-line technique originated from [45] is used. Many broadband and also high directivity couplers in inhomogeneous media have been reported [26,29,[46][47][48][49][50][51][52][53][54][55][56][57][58][59], but there is little information about maximum operating frequencies beyond 20 GHz and their special design requirements [27,28,30,60]. A comprehensive comparison of reported and commercially available backward wave couplers with the proposed coupler is given in Table 3.2.…”

A Novel 3-dB Trans-directional Coupler with DGS and Conductor-backed Asymmetric Coplanar Waveguides

“…When the coupled lines are loaded by periodical shunt capacitors, the equivalent even-and odd-mode characteristic impedances are named as Z 0e and Z 0o . For a uniform symmetric coupler, the following relations are satisfied [22,23]:…”