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RF Choke - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


SilencerEx
Post subject: RF Choke
Unread postPosted: Tue May 24, 2005 5:53 am
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Captain

Joined: Tue May 24, 2005 5:41 am
Posts: 5
Hi, I've build a class A microwave amplifier for the frequency range 1GHz to 3 GHz with discrete components. Here's the schematic:
Image
The power gain is 15 dB at 1GHz and 3 dB at 3GHz.

It's working fine, but I think the RF chokes are limiting the gain. At the moment I'm using AVX Accu-L inductors which have a self resonance frequency of 1.8 GHz but they have a small inductance. What kind of choke is commonly used in this frequency range?


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Guest
Post subject:
Unread postPosted: Tue May 24, 2005 9:00 am

Your right, the choke will be limiting your gain. The self resonance needs to be above 3GHz. Look at coilcraft, they should have something that will work. If price is no object, then you can use a conical inductor, they operate up to 40GHz. They are sold by piconics, www.piconics.com.


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SilencerEx
Post subject: Re
Unread postPosted: Tue May 24, 2005 10:28 am
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Captain

Joined: Tue May 24, 2005 5:41 am
Posts: 5
Thanks for your reply, so I just need inductors with a high self resonance frequency. I've been ordering stuff at Farnell, but they don't have a lot of microwave components. Does anyone know a supplier in Europe which can deliver microwave components in small quantities within the week?


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Guest
Post subject:
Unread postPosted: Tue May 24, 2005 3:16 pm

Hello,

Coilcraft can provide you samples within a short time. I think that you can even order samples throughout their website www.coilcraft.com

I have done that many times before. Their coils are excellent. They even have models which you can use in Microwave Office. If I recall correctly there are built-in models in the Microwave Office for their wire-wound coils.

You can also use Taiyo-Yuden chip inductors, they also give samples within short time.


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SilencerEx
Post subject: Re
Unread postPosted: Tue May 24, 2005 6:23 pm
Offline
Captain

Joined: Tue May 24, 2005 5:41 am
Posts: 5
That's great news. I'll try it out immediatly.



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