A high frequency circuit with variable phase shift

摘要

To make a variable phase shifter at low cost and that is easy to manufacture, two propagation paths (3, 4) for a high frequency signal are provided in parallel between the input (1) and the output (2) of the phase shifter. These two paths are of different lengths. An intermediate node (7) on one of the paths is connected to an intermediate node (9) on the other path by a PIN diode (5). The diode is connected to the paths by a segment of line (24) further enhancing the length difference. By biasing (14-19) the diode to a desired level, it is caused to present a particular impedance to propagation. It is shown that by acting in this way the diode can vary the phase shift between the input and the output without needing to use harmful reactive components. <IMAGE>