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chandregowda
Joined: 07 Jul 2008
Posts: 205
Helped: 9
Location: Bengaluru/Bangalore, India
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 11 Dec 2008 9:33 wideband coupler: Peaks in the response |
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hi,
i have designed a wideband coupler(700MHz-6000MHz) using asymmetric multisection stripline configuration. the design was simulated in HFSS and Microwave CST.
In the S-parameters response, HFSS was showing peaks at higher frequencies
after fabrication, the prototype is also showing few peaks at higher frequencies....
how to eliminate these peaks in the response?
this helps me a lot..........
thanking you
chandre
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VSWR
Joined: 07 Feb 2002
Posts: 767
Helped: 72
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11 Dec 2008 23:21 Re: wideband coupler: Peaks in the response |
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| Could be many reasons. WinRAR your project files and post here.
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11 Dec 2008 23:21 Ads |
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yendori
Joined: 29 Jul 2005
Posts: 120
Helped: 10
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12 Dec 2008 16:17 Re: wideband coupler: Peaks in the response |
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At least your sim matches your measured data:D
Your coupler is resonating. What type of board are you using?
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chandregowda
Joined: 07 Jul 2008
Posts: 205
Helped: 9
Location: Bengaluru/Bangalore, India
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15 Dec 2008 8:27 Re: wideband coupler: Peaks in the response |
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hi,
No substrate board, Air as the dielectric, it is cavity type coupler.
HFSS simulations matching with measured results.
The model consists of 2 parallel coupled lines. multiple sections (N=5) are used to get more bandwidth. Each section is λ/4 long (equal length), the bandwidth is
700-6000MHz.
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kspalla
Joined: 19 Aug 2008
Posts: 848
Helped: 140
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15 Dec 2008 13:29 wideband coupler: Peaks in the response |
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| Cavity may be self resonating, so check for this.
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chandregowda
Joined: 07 Jul 2008
Posts: 205
Helped: 9
Location: Bengaluru/Bangalore, India
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17 Apr 2009 5:52 Re: wideband coupler: Peaks in the response |
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hi,
cavity is resonating, peaks were removed by optimizing the cavity width in simulation software. after this return loss at few points is -10dB. fabricated model also showed similar response, but a little variation.
i am trying to improve the return loss to -15dB with the addition of stubs in simulation software.
if there are any other ways to improve the return loss, pl. let me know.
Frequency of operation-700MHz-6000MHz
thank you
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kspalla
Joined: 19 Aug 2008
Posts: 848
Helped: 140
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17 Apr 2009 6:57 wideband coupler: Peaks in the response |
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| Can you describe with the pictures so that we can understand or PM me the design if you do not wish to share in the forum.
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