These amplifiers can be used in millimeter-wave imaging systems for weapons detection and airport security, and for radar instruments.
Two single-stage InP heterojunction bipolar transistor (HBT) amplifiers operate at 184 and 255 GHz, using Northrop Grumman Corporation’s InP HBT MMIC (monolithic microwave integrated circuit) technology. At the time of this reporting, these are reported to be the highest HBT amplifiers ever created. The purpose of the amplifier design is to evaluate the technology capability for high-frequency designs and verify the model for future development work.
MMIC amplifier operating frequencies have pushed past 200 GHz and into submillimeter wave frequencies. The main driver has been in demand for millimeter-wave radiometers and high-resolution, all-weather imaging systems.
MMIC power amplifiers have a variety of applications for ground-based and future space-based telescopes for astrophysics, as well as in local oscillators for heterodyne receivers in Earth and planetary science instruments. They can be used in millimeter-wave imaging systems to provide sensitive hidden-weapons detections, airport security imaging systems, or other homeland security portable imaging sensors. Power amplifiers can also be used in transmitters for radar instruments and commercial laboratory power sources.
While HEMT amplifiers are traditionally used for low noise receivers due to their low noise properties, HBT amplifiers can be used as power sources due to the nature of their material properties, traditionally higher breakdown voltages and potentially higher efficiency.
A demonstration of the MMIC HBT amplifier showed results approaching the sub-millimeter-wave regime (~300 GHz) and showed the highest reported gain of 3.5 dB for a single-stage HBT amplifier at 255 GHz. The common emitter topology was chosen due to its stability at high frequencies. Distributed transmission lines and matching components were realized using an inverted microstrip configuration, and were im - plemented in a two-metal process with BCB (benzocyclobutene) dielectric. The primary advantage of this configuration is low inductance to ground compared with traditional microstrip designs.
This work was done by Vesna Radisic, Donald Sawdai, Dennis Scott, William Deal, Linh Dang, Danny Li, Abdullah Cavus, Richard To, and Richard Lai of Northrop Grumman Corporation, and Lorene Samoska, King Man Fung, and Todd Gaier of Caltech for NASA’s Jet Propulsion Lab - oratory. The contributors would like to acknowledge the support of Dr. Mark Rosker and the Army Research Laboratory. This work was supported by the DARPA SWIFT Program and Army Re - search Laboratory under the DARPA MIPR no.06-U037 and ARL Contract no. W911QX-06-C- 0050. NPO-45465