A high-gain monolithic D-band InP HEMT amplifier

This paper describes a three-stage monolithic amplifier that exhibits a small-signal gain of 30 dB at 140 GHz. The amplifier employs AlInAs/GaInAs/InP high electron mobility transistor devices with 0.1×150 μm² gate periphery, is implemented with coplanar waveguide circuitry fabricated on an InP substrate, and occupies a total area of 2 mm². Gain exceeding 10 dB was measured on-wafer from 129 to 157 GHz. This is the highest reported gain per stage for a transistor amplifier operating at these frequencies     

Active integrated antennas

Even with microwave techniques, however, signal losses in materials and decreased gain and power from solid-state devices become significant obstacles to creating low-cost, high-frequency wireless systems. Perhaps the most dramatic effect occurs when a circuit component becomes a significant fraction of a wavelength. At this point it may begin to function well as an antenna. For microwave and mm-wave signals, this can occur with circuits that are only centimetres in size. With conventional circuit techniques, this radiation may cause drastic signal losses, spurious coupling between circuit elements, and radio interference with other. However, with new techniques, it is possible to create circuits that use these effects to advantage. Known as active integrated antennas, these circuits have sparked interest as possible solutions to problems in designing the next-generation wireless systems. Active integrated antennas are a combination of solid-state devices and circuits with printed antenna structures. They comprise integrated radio-system elements that are fabricated using inexpensive printed-circuit techniques