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and Reel for Pick and

Place Manufacturing.

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(315) 432-8909

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Model X3C21P1-03S

Rev C

the interface pad will have less capacitive reactance than the Anaren test board. In this case, a wider section of line

before the interface pad (or a larger interface pad) will introduce a shunt capacitance and when properly tuned will

match the performance of the Anaren test board.

Notice that the board layout for the 3dB and 5dB couplers is different from that of the 10dB and 20dB couplers. The

test board for the 3dB and 5dB couplers has all four traces interfacing with the coupler at the same angle. The test

board for the 10dB and 20dB couplers has two traces approaching at one angle and the other two traces at a different

angle. The entry angle of the traces has a significant impact on the RF performance and these parts have

been optimized for the layout used on the test boards shown below.

3 dB and 5dB Test Board

Testing Sample Parts Supplied on Anaren Test Boards

If you have received a coupler installed on an Anaren produced microstrip test board, please remember to remove the

loss of the test board from the measured data. The loss is small enough that it is not of concern for Return Loss and

Isolation/Directivity, but it should certainly be considered when measuring coupling and calculating the insertion loss

of the coupler. An S-parameter file for a “Thru” board (see description of “Thru” board above) will be supplied upon

request. As a first order approximation, one should consider the following loss estimates:

Frequency Band

Avg. Ins. Loss of Test Board @ 25°C

869-894 MHz

~0.064dB

925-960 MHz

~0.068dB

1805-1880 MHz

~0.119dB

1930-1990 MHz

~0.126dB

2110-2170 MHz

~0.136dB

The loss estimates in the table above come from room temperature measurements. It is important to note that the

loss of the test board will change with temperature. This fact must be considered if the coupler is to be evaluated at

other temperatures.