Microstrip balun-antenna apparatus

Claim 1

A balun apparatus having an unbalanced port and a balanced port comprising: a single substrate of dielectric material having first and second major surfaces; a microstrip transmission line situated on said substrate and having an input and an output; a microstrip balancing section situated on said substrate and having an input and an output, said section including two substantially parallel conductors situated on said first surface and mutually connected at opposite first and second ends, said first end being coupled to said transmission line output and being defined as the unbalanced port of said balun apparatus, said section further including two substantially parallel conductors on said second surface, each of said second surface parallel conductors including third and fourth opposed ends, said second surface parallel conductors being mutually connected at said third ends to said transmission line output; said second end of said first surface parallel conductors being directly connected via a feedthrough through said substrate to one of the fourth ends of said second surface parallel conductors, the fourth ends of said second surface parallel conductors being defined as the balanced port of said balun apparatus.