V. A. Pechurin, A. S. Petrov
This paper proposes the circuits, structures and characteristics of three classes of VHF power divider-combiners (PDC) used for middle and high signal power. The characteristics of directional coupler based on coupled coaxial lines fabricated by Sage Laboratories Inc. are also experimentally investigated.
The proposed PDC has good characteristics nearly in octave bandwidth: reflectivity factor from inputs and isolation are no more than -25 dB and power division factor non-uniformity is no more than 0.75 dB.
Two PDC circuits based on branch-line quadrature couplers, which provide reflectivity factor from inputs and isolation between lines in bandwidth 30% no more than -20dB and power division factor non-uniformity no more than 0.25 dB, are proposed.
The first circuit is realized on the base of three-stubs branch-line coupler. In order to expand device power capability, first (external) parallel stubs are replaced by compact 5-element low-pass LC-filer.
The second PDC circuit is realized on the base of two-stubs branch-line coupler with reduced base region input impedance and input quarter-wave length transformers. It is fabricated in microstrip implementation on the ceramic substrate with relative dielectric constant εr=80.