Variable Attenuator with Low Phase Shift

A new base structure of the voltage-controlled phase invariant attenuator is described. This structure is based on T-attenuator with phase decoupling circuits. Design factors for decreasing the phase shift are discussed. A computer-aided design technique for minimizing phase shift in attenuator is presented. Measured attenuation of one section up to 15 dB is shown to be independent of frequency band up to 3 GHz. The adjusting parameters for one-stage attenuator were founded. Novelty of this paper consists in application of theorem of the minimum phase shift for the linear attenuator design