XC0900A-05 Datasheet, PDF (20/21 Pages) Anaren Microwave – 5 dB Directional Coupler

Model XC0900A-05
Rev D
Application Information
The XC0900A-05 is an “X” style 5dB coupler. Port configurations are defined in the table on page 2 of this data sheet
and an example driving port 1 is shown below. Note that this is not an “H” style coupler like the older 5dB Xinger
couplers (such as the 1D1304-5 and 1A1305-5). The change was made to allow better placement of the termination
resistors when the coupler is used in a serial splitter/combiner network.
Ideal Coupler Operation
1V
1
4
0.562V∠θ (-5dB)
Isolated Port 2
3
0.827V ∠θ -90 (-1.65dB)
The primary application for 5dB couplers is in serial splitting and combining networks. These networks are often
employed when the combining of 3 amplifiers is required. Unlike corporate networks, serial networks are not limited to
binary divisions (corporate networks are limited to 2 ⁿ number of splits, where n is an integer). Serial networks can be
designed with [3, 4, 5, ….., n] splits, but have a practical limitation of about 8 splits.
A 5dB coupler is used in conjunction with a 3dB coupler to build 3-way splitter/combiner networks. An ideal version of
this network is illustrated below. Note what is required; a 50% split (i.e. 3dB coupler) and a 66% and 33% split (which is
actually a 4.77dB coupler, but due to losses in the system higher coupler values, such as 5dB, are actually better suited
for this function). The design of this type of circuit requires special attention to the losses and phase lengths of the
components and the interconnecting lines. A more in depth look at serial networks can be found in the article “Designing
In-Line Divider/Combiner Networks” by Samir Tozin, which describes the circuit design in detail and can be found in the
White Papers Section of the Anaren website, www.anaren.com.
3-Way Ideal Serial Splitter/Combiner Network
5 dB (4.77)
Pin
coupler
1/3 Pin
1/3 Pin _{3 dB coupler}
G=1
* 50Ω
Termination
* 50Ω
Termination
2/3 Pin
1/3 Pin
2/3 Pin
3 dB coupler
1/3 Pin
G=1
5 dB (4.77)
coupler
* 50Ω
Termination
* 50Ω
Termination
1/3 Pin
1/3 Pin
Pout
G=1
*Recommended Terminations
Power (Watts)
Model
8
RFP-060120A15Z50
15
RFP-250375A4Z50
50
RFP-375375A6Z50
100
RFP-500500A6Z50
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