Micro Harmonics offers a line of millimeter-wave Y-junction circulators in the WR-15, WR-12, WR-10 and WR-8 bands covering the spectrum from 50-140 GHz. These circulators exhibit state-of-the-art performance in terms of low-insertion loss, broad-bandwidth, and low port reflections.

Our Y-junction circulators do not employ complicated dielectric matching elements. Rather, the impedance matching circuitry is implemented through precision CNC machined features in the waveguide block which are highly repeatable and tightly controlled. The machined structures also make it easy to align the ferrite cores with some precision and obtain a high degree of uniformity between the three circulator ports.
Model Name Flange
20 dB Band*
Insertion Loss
(dB, max)
(dB, min)
YC148-61 WR-15 58 – 64 0.4 20
YC148-68 WR-15 65 – 71 0.5 20
YC122-73 WR-12 71 – 76 0.5 20
YC122-78 WR-12 75 – 81 0.5 20
YC122-83 WR-12 81 – 86 0.6 20
YC100-86 WR-10 83 – 89 0.6 20
YC100-93 WR-10 90 – 95 0.7 20
YC100-95 WR-10 92 – 98 0.7 20
YC100-97 WR-10 94 – 100 0.7 20
YC100-105 WR-10 102 – 108 0.7 20
YC80-110 WR-8 107 – 113 1.1 20
YC80-118 WR-8 115 – 120 1.1 20
YC80-127 WR-8 125 – 129 1.1 20
* The band over which the isolation is greater than 20 dB.

Our initial offerings are targeted to bands where there is widespread interest in the millimeter wave community. Over time we will continue to add products tuned to other sub-bands within the 50-140 GHz window in response to customer requests. Designs above 140 GHz will be considered on a case-by-case basis.

Please do not hesitate to contact us to discuss how we can apply our capabilities to your requirements. We typically do not charge a design fee (NRE) to develop a circulator tuned to a specific sub-band. Our primary concern is to identify bands of interest and provide components to serve the broader community.

“We couldn’t find anybody that was capable of producing circulators in the frequency band we required, much less with the high isolation and wide bandwidth we wanted… Micro Harmonics fine-tuned the design to meet the performance characteristics we needed within a very precise band.”

Dr. Fred Daneshgaran, Professor, Chairman
California State University, Los Angeles

We define the bandwidth as the band over which a circulator has more than 20 dB isolation. The graph below gives an estimate for the 20 dB bandwidth that can be achieved at a given center frequency. For example, a circulator designed with a center frequency of 110 GHz has a fractional bandwidth near 5%. The isolation would be greater than 20 dB across the band 107.3-112.7 GHz.

A typical Y-junction circulator specification sheet is shown below. The circulators can also be tuned for higher isolation over more narrow bandwidths. The three flanges are equidistant from the Y-junction.