Title :
High Directivity Microstrip Couplers Using Dielectric Overlays
Author :
Buntschuh, Charles
Author_Institution :
Microwave Assoc., Inc., Burlington, MA, USA
Abstract :
Coupled-line directional couplers in microstrip suffer from low directivity due to the inequality of the even and odd mode wave velocities. A dielectric overlay improves the directivity, but it also tightens the coupling and depresses the coupler impedance. Design curves are presented for making velocity-compensated 50 ohm couplers taking the changes in coupling and impedance into account.
Keywords :
impedance matching; microstrip directional couplers; coupled-line directional couplers; coupler impedance; coupling; design curves; dielectric overlays; even mode wave velocity; high directivity microstrip couplers; odd mode wave velocity; resistance 50 ohm; velocity-compensated couplers; Couplers; Coupling circuits; Dielectric constant; Dielectric substrates; Distributed parameter circuits; Impedance; Microstrip; Stripline; Strips; Transmission line theory;
Conference_Titel :
Microwave Symposium, 1975 IEEE-MTT-S International
Conference_Location :
Palo Alton, CA
DOI :
10.1109/MWSYM.1975.1123304
