Abstract: A low pass filter exhibiting low loss, low reflection, and Gaussian phase distortion characteristics at microwave and radio frequencies is provided. The low pass filter may comprise a negative feed forward network having a first directional coupler having a resonant frequency f.sub.0 and a second directional coupler having a resonant frequency f.sub.0, a through port of the first directional coupler being coupled to a through port of the second directional coupler, a coupled port of the first directional coupler being coupled to a coupled port of the second directional coupler, and an isolated port of the first directional coupler and an isolated port of the second directional coupler being terminated in matched loads. Additional embodiments employing multiple negative feed-forward networks are also disclosed.

Abstract: A discrete phase shifter and a method for discrete phase shifting in which an input signal is split into two signals. One of the split signals is phase shifted by a first fixed amount by a first fixed phase shifter cell, and the other split signal is phase shifted by a second fixed amount by a second fixed phase shifter cell. A selector is utilized to select at least one of the two split phase shifted signals and to input these to a vector summer. The vector summer synthesizes an output signal that is phase shifted with respect to the input signal. In this manner, the output signal is discretely phase shifted either by the first fixed amount, the second fixed amount, or, by selecting both of the split signals prior to vector summing, the sum of these amounts.