Directional Couplers

*NOTE: For 2.92 mm add "K" to the end of the Model Number.

Common Definitions

Microwave Frequency Bands
Band Designation	Frequency Range (GHz)
UHF	300 MHz - 1.0 GHz
L	1.0 - 2.0
S	2.0 - 4.0
C	4.0 - 8.0
X	8.0 - 12.0
DBS	12.2 - 12.7
Ku	12.0 - 18.0
K	18.0 - 26.5
Ka	26.5 - 40.0
Q	30.0 - 50.0
U	40.0 - 60.0
V	50.0 - 75.0

Couplers are passive microwave components used for distributing or combining microwave signals. Directional couplers are four-port circuits where one port is isolated from the input port. The coupled port on a microstrip, or stripline directional coupler, is closest to the input port because it is a backward wave coupler. On a waveguide broadwall directional coupler, the coupled port is closest to the output port because it is a forward wave coupler. VSWR is defined as the ratio of the maximum voltage to the minimum voltage in standing wave pattern along the length of a transmission line structure. It varies from 1 to (plus) infinity and is always positive. Insertion Loss is the net unrecoverable power in dB dissipated within the circuit at any frequency within the specified range. Frequency Sensitivity is the amount of frequency change in the carrier frequency per unit amplitude change in the message signal.

Additional Resources

For more information on Krytar's Couplers please see below:

• Directional Coupler Primer Page
• Microwave or RF Amplifier Test Setup
• Krytar Directional Couplers: Term Definitions, Testing, and Typical Applications.
• Coaxial Coupler and Directional Detector Sample 2 to 40 GHz - Microwaves & RF article, May 1987
• Krytar Directional Coupler 2 – 50 GHz