Microstrip to coplanar strip double-Y balun with very high upper frequency limitation

Abstract

Double-Y balun is a kind of printed balun with ultra wide bandwidth, which can also realize transformation from different sorts of printed transmission lines and has been widely used in wideband mixer and ultra-wideband antennas. This paper researched on some elements that influent the upper frequency limitation of double-Y balun in practical engineering and presented a design of double-Y balun transition from microstrip line to coplanar strip line (CPS) with pass band up to 18GHz. The design also included a Microstrip impedance transformer as this design is to feed a 100 vivaldi antenna. The VSWR of whole component was less then 1.5 and insert loss 2dB in a bandwidth of over 1: 18.

A 60-GHz on-chip tapered slot Vivaldi antenna with improved radiation characteristics

“…It has various realizations with the same equivalent circuit as the transmission lines differ. Previous researches have investigated double-Y balun theoretically [7,8] and practically [9][10][11][12][13].…”