The antenna port feed to the T/R channel usually passes through a ferrite circulator
, often with a ferrite isolator to protect the power amplifier, or occasionally with a high power T/R switch that can terminate the receive path with a load during the transmit pulse cycle.
Reliability of a ferrite circulator
switch is 0.1 FITS in the spaceflight environment.
Another example is a ferrite circulator
, where even modest heating can bring the ferrite above the Curie temperature and disable it.
of Harvard, MA has acquired the ferrite circulator
, isolator and attenuator product lines of MCCI Wireless and P&H Laboratories.
The CT-1510-S special series of ferrite circulators
is rated at 2 kW average/CW and 10 kW peak power for use in the digital and HDTV UHF television hands.
are capable of providing robust performance for typical GaAs X-band applications and can support wide bandgap output power levels.
Contractors and tasks for this thrust are Cascade Microtech, next-generation mm-wave probes, Electromagnetic Sciences Technologies Inc., miniaturized ferrite circulators
for MMIC applications; Hittite Microwave, large-scale integration of advanced MMICs for microwave frequency synthesizers; ITT Avionics, low cost common MMIC components for electronic warfare transmitter arrays; Lockheed Martin, Syracuse, NY, high yield mm-wave indium phosphide high electron mobility transistor MMICs and a mm-wave load-pull test station; Lockheed Martin, Baltimore, MD, high indium low cost FET materials on GaAs; and Lockheed Martin, Moorestown, NJ, a 50 W plastic high density interconnect module.
Therefore, for frequencies above approximately 3 GHz, a large DC bias field is required for operation above resonance; for these higher frequencies, most ferrite circulators
operate biased below resonance.