How to design a directional coupler with Lumped LC net works

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dingjingfeng

Joined: 12 Aug 2005
Posts: 196
Helped: 9

30 Jul 2007 12:56 How to design a directional coupler with Lumped LC net works

the application is to prevent the signal reflection from antenna.

VSWR

Joined: 07 Feb 2002
Posts: 767
Helped: 72

31 Jul 2007 15:33 Re: How to design a directional coupler with Lumped LC net w

http://www.odyseus.nildram.co.uk/RFMicrowave_Circuits_Files/Hybrid.pdf

http://michaelgellis.tripod.com/direct.html

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Mosieur_Oiso

Joined: 24 Jul 2007
Posts: 22
Helped: 2

31 Jul 2007 15:49 Re: How to design a directional coupler with Lumped LC net w

To prevent signal reflection from antenna? Wouldn't you rather need an isolator?
Mosieur_Oiso

dingjingfeng

Joined: 12 Aug 2005
Posts: 196
Helped: 9

31 Jul 2007 17:07 How to design a directional coupler with Lumped LC net works

isolator
OK
How to design it with lumped LC networks?

Mosieur_Oiso

Joined: 24 Jul 2007
Posts: 22
Helped: 2

25 Oct 2007 18:11 Re: How to design a directional coupler with Lumped LC net w

Hi there,
Yes, that is possible, but not using LC SMD components. You will need a ferrite disk and you will have to wind 3 coils around it at 120 degree angle (see the article there is a nice picture of it...)
Depending on your application and frequency, you might better get one from a component manufacturer, I happened to use miniature isolators from TDK (but this is just one example), you can find different models on their website: http://www.tdk.co.jp/tefe02/rf_network.htm#aname5
You can request some samples through one on their sales offices, but usually this doesn’t go very fast Sad

Good luck!
Mosieur_Oiso

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Shoma Chandorkar

Joined: 27 Jun 2007
Posts: 17
Helped: 1

27 Nov 2007 11:00 How to design a directional coupler with Lumped LC net works

You can refer to the Chapter 12 of the "Lumped element for RF and Microwaves circuit" by Inder Bahl.(Page No364-366). calculation of L & C value is giventher.