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microwave amplifier stub matching design

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Full Member level 5
Aug 11, 2004
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Wideband Matching


I need to design wide band stubs (Open & Short). I try Radial stub and it works for

short circuit, but for open circuit i used a λ/4 stub with radial stub and because of

low bandwidth of λ/4 stub it doesn't work.does anyone know how can i increase

the bandwidth of a λ/4 stub?(for example using multiple stages)

does anyone have any good resource for wide band matching circuit design?


Wideband Matching

There is a paper of Fano on Wideband Circuit matching..but it is very mathematical one...and also...I think it is not IEEE paper..but u can search under UWB case for windeband is same..UWB Antenna matching...

Re: Wideband Matching


First Thank you for your reply.

I think i should explain my problem :

I have a wide band 1W MMIC Amplifier,that i must using it's output RF power pin

for DC Supply. Usually i used a Bias-TEE for this purpose but a Wide band Bias-Tee

has about 1~1.5dB insertion Loss.I want to find another solution to avoid that Loss.
(Maximum 0.5dB Loss is acceptable).

My FREQ. Range is 6~12 GHz. Does anyone have any solution?

My MMIC have a Output Return Loss < -10dB (VSWR~2) in it's bandwidth.


Re: Wideband Matching

Hi Balaguru,
Acatully original paper written by Fano is not avaliable anywhere online.(If anyone has it pls upload it) and the reason people don't refer to it coz it is very mathematical one.I got to see it in our library sometimes back but now it is not there.
Here I am uploadingthree papers which are related to to topic and hope you will find it helpful.
This Fano case study is widely used as limit case and can be seen in UWB antenna topics.
If you have UWB Antenna books you can check it for the same.

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