A Compact and Wideband Coupled-Line Coupler with High Coupling Level Using Shunt Periodic Stubs
MetadataShow full item record
A wideband microstrip forward-wave coupled-line coupler with high coupling value is presented. Compared with the conventional edge-coupled microstrip forward-wave coupler, this symmetrical structure, consisting periodic shunt stubs between the two coupled-lines, achieves wider operating bandwidth and larger coupling level. To characterize this structure, the equivalent circuit model is established and verified by measurement and full-wave results. The designed and fabricated prototype is a 0-dB forward-wave coupler with 0.6 mm stub length. This coupler exhibits a coupled amplitude balance of ±2 dB, good matching (15dB) and at least 15dB isolation between adjacent ports over a wide bandwidth of 66% from 2 GHz to 4 GHz centered at 3 GHz. The coupled-line length and width of the proposed structure are approximately λg/2 and λg/13, respectively, which makes it more compact than the conventional forward coupled-line couplers.
KeywordsCoupled-line couplers, periodic structures, forward-wave couplers, shunt stubs, wideband microwave devices.
Document typePeer reviewed
Document versionFinal PDF
SourceRadioengineering. 2013, vol. 22, č. 1, s. 323-327. ISSN 1210-2512
- 2013/1