A broadband balanced idler circuit for parametric amplifiers

The bandwidth of the idler circuit of a parametric amplifier is discussed, and reductions in bandwidth associated with stray reactances of the diode encapsulation and filter networks required to complete the idler circuit are described. A balanced idler circuit using two diodes is shown to approach the theoretically maximum idler bandwidth. A 3000 Mc/s amplifier is described having a 10% bandwidth at 20 dB gain.