Impedance Transformations For The Generalized Reflection Modulator

Abstract

SENIOR MEMBER, IEEE .4 bstrad-A procedure is given for obtaining the impedance transformer which will produce a prescribed pair of phasor reflection coefficients by transformation from a given pair of impedance states terminating the transformer. The transformer may be used in a general two-state reflection modulato~as a phase shifter with phase change at constant amplitude or as an amplitude modulator with level shift at constant or variable phase. The condition governing the reflection coefficients available from a given pair of impedance states is given. Examples and limitations are discussed.

Application of GaAs Discrete p-HEMTs in Low Cost Phase Shifters and QPSK Modulators

“…Table 2 shows the summarized values of the losses of each component in (2). The calculation for the insertion loss of 180° phase-shifting bit IL RB is made by the help of (3) reported in [5] and uses the calculated quality factor of the discrete p-HEMT switch, 2 Q = 781.…”

“…State of the art mobile satellite communications are closely related to the application of phase control devices such as phase shifters and phase modulators as a part of transmit-and receivephased array antennas [1], [2]. In the past, the development of high-performance discrete and hybrid phase shifters and modulators operating in X and Ku bands was based on beam lead p-i-n diodes used as a main switching component [3]- [5]. Beam lead p-i-n diodes have excellent microwave properties such as low resistance in low impedance states and low capacitance in high impedance states.…”