Balanced distributed-element phase shifter

We present a balanced distributed-element phase shifter based on a nonlinear transmission line (NLTL) structure. Results show the second harmonic is more than 13dB lower at 0-V bias than a conventional single-ended NLTL phase shifter. We fabricated both balanced and conventional NLTL phase shifters with the same coplanar waveguide (CPW) design and diodes, and observed that phase shifting and insertion loss for both structures were quite similar, yet harmonic distortion was greatly improved in the balanced structure.