Abstract: A power amplifier circuit includes an adjustable gain power amplifier for amplifying an RF input signal. An isolated node in the adjustable gain power amplifier is isolated from the output load by a gain stage of the adjustable gain power amplifier. The power level of a signal at the isolated node corresponds to the power level of a signal at the output load. A detector is either capacitively coupled to the isolated node or connected by a direct current (DC) connection. The detector detects the power level of the signal at the isolated node. The detector generates a power level indicator that is sent to a gain control circuit. The gain control circuit adjusts the gain of the adjustable gain power amplifier to maintain a constant drive level at the isolated node.

Abstract: A power amplifier circuit includes an adjustable gain power amplifier for amplifying an RF input signal. An isolated node in the adjustable gain power amplifier is isolated from the output load by a gain stage of the adjustable gain power amplifier. The power level of a signal at the isolated node corresponds to the power level of a signal at the output load. A detector is either capacitively coupled to the isolated node or connected by a direct current (DC) connection. The detector detects the power level of the signal at the isolated node. The detector generates a power level indicator that is sent to a gain control circuit. The gain control circuit adjusts the gain of the adjustable gain power amplifier to maintain a constant drive level at the isolated node.

Abstract: A time delay shifter imparts a constant time delay to an electromagnetic signal, preferably a signal at a microwave frequency, over a band of frequencies. The phase shift imparted to the signal is a linear function of frequency. The shifter comprises a finite number of delay units (1) each having four single-pole single-throw switches (11-14). Closure of the first and third switches (11, 13) causes the signal to traverse a first path (2) containing a preselected length of transmission line that imparts a fixed time delay to the signal. Closure of the second and fourth switches (12,14) causes the signal to traverse a minimum-delay path (3) which is shorter than the delay path (2). The paths (2,3) are fabricated of coplanar waveguide. Each switch (11-14) is resonated by an inductor (21-24) for purposes of increasing isolation. An attenuator (70) is inserted in each minimum-delay path (3).