13.6 GHz output signal of ADF5356 synthesizer chip

13.6 GHz output signal of ADF5356 synthesizer chip. The ADF5356 has an on-chip VCO from 3-6.8 GHz and outputs twice its frequency on a pin.

Looks like the doubler has a serious symmetry problem. The 2*f output is the strongest component, but just barely. And the level is also on the weak side.

That requires some serious microstrip filters. :-(

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cheers, Gerhard

Reply to
Gerhard Hoffmann
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Sinewave purity isn't the norm at high frequencies. I've seen fancy HP rf sig gens with visible distortion too. They tend to proudly display low close-in spurs and ignore the stuff an octave up, or down in your case.

Can you use a coaxial ceramic resonator to clean it up?

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
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Reply to
jlarkin

Am 01.10.20 um 17:21 schrieb snipped-for-privacy@highlandsniptechnology.com:

That would be a dielectric resonator on 10 GHz. I have one in different oscillator in this box. I'm still struggling to get valid s-parameters from EM-simulations of the puck.

The synthesizer is there to provide a tuneable beat frequency. I've made a ring resonator to notch out the fundamental.

I've made a ring resonator that makes a nice trap for the fundamental. This one is scaled down to 3.5/7GHz since I'm VNA challenged.

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Board material is Rogers TMM6, 25mil. It has the consistency of cold wax, or of an eraser. Breaks when one looks hard at it.

The filter is self-etched. Laser-printed to foil and exposure on light-sensitive laquer. I have peeled away some copper on the top side so see if that has an effect. It had none.

Cheers, Gerhard

Reply to
Gerhard Hoffmann

Looks like the surface-mount CCRs top out at about 10 GHz.

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Reply to
John Larkin

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Yep--and that is really pushing it. The upper limit used to be about 6 GHz not too long ago. This filter should be printed (planer). Gerhard already d id the fundamental trap as printed.

You can see elsewhere that IMC has stopped selling individual resonators (h ttps://

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IMC has traditionally had one of the best (highest Q) resonator plating processes. ComNav (Marty Geesaman,
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is the other. IMC's founder, Dennis R. Cl ark, passed away in 2015, and his wife now runs the company.

CTS does monoblock BPF, but they stop sub 8 GHz. CTS is for higher volume. I don't think muRata is even bothering with mono-block anymore. NTK used to have both monoblock and LTCC stuff, but seem to have dropped out of that b usiness altogether.

Reply to
Simon S Aysdie

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