Yet another coupler

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I4LEC
Posts: 28
Joined: Sun Apr 09, 2017 2:58 pm

Yet another coupler

Postby I4LEC » Tue Jan 16, 2018 1:40 pm

Originally thought for a more conventional use, a bidirectional monoband coupler designed for a commercial solid state PA.

Main characteristics are:

Max input power 63dBm (2.000W)
IN/OUT impedence 50 Ohm
Coupling factor -45dBm @ 28MHz

Certainly a totally different approach from conventional ones, as being monoband, the coupling factor will change radically from 10m down to 160m, by a factor of 20dB, which is what normally we try to avoid, on the other hand, it only takes a piece of FR3 PCB of 3.2mm thickness, few connectors and a box.

Well, taking the advantages of the automatic PS attenuator, I discovered that 20db are just right for my setup, as a span of 200W to 2kW will fit perfectly.

The microstrip width turned out to be 5,8mm, for a coupling factor of -45dB, the length 48,6mm.

Attached, per band attenuation table and in and out view of the coupler

73, Clay
Attachments
Attenuatore2.xlsx
(5.67 KiB) Downloaded 338 times
Coupler2.jpg
Coupler2.jpg (59.03 KiB) Viewed 4650 times
Coupler.jpg
Coupler.jpg (28.67 KiB) Viewed 4650 times

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