Abstract: The inventions presented herein provide a electronically controlled phase shifters that incorporate analog and digital phase shift architectures in a novel manner that realizes the best advantages of each architecture. This combination of complementary phase shift architectures provides the high-performance and low loss characteristics of switched digital phase shift architectures with the high resolution and precision of continuous analog phase shift architectures. The circuit embodiments are electronically controlled, which simplifies implementation of what is a complex circuit. The analog phase shift elements comprise electronically-tuned varactors, which provide fine resolution and enables the incorporation of active compensation for manufacturing variation before use or for environmental conditions during use.

Abstract: An intersub-valence band quantum well detector (52), comprising alternating quantum wells (30') and barriers (32'), provided with differential strain permits obtaining hole mean free paths similar to the electron. Consequently, the gain and responsivity should dramatically increase. In addition, the absorption coefficient should increase, while the noise current should decrease; thus, the quantum efficiency and the detectivity (D*) should increase, compared to a detector without the added differential strain.