File:CH 9.jpg

Operating schematic for the Raytheon polarization switch. This switch used the magnetization state of ferrite material to control the direction in which microwaves propagated around a circulator. The dashed vertical lines in the lower portion of the figure show the application of DC current pulses sent through coils surrounding the circulator’s ferrite material. Alternating the polarity of these current pulses reversed the direction of the ferrite’s magnetic fields, varying the microwave propagation direction through the circulator between the CW and CCW directions shown in the upper portion of the figure. The speed with which these magnetic field reversals could be done allowed transmit polarization to be changed on a pulse to pulse basis, improving the Zdr measurement speed. The CHILL radar collected the first Zdr data using the Raytheon switch in late July 1981 during the CCOPE project. Raytheon switches were fitted to the NCAR CP2 and the NSSL Cimarron radars in 1983 and 1986 respectively. The drawing in this figure was scanned from a radar conference preprint written by Gene Mueller in the early 1980’s.