Changeabel RF-Filter for PCB Layout
But for the higher Frequency I need on the Output of the VCO a narow band edge coupled filter. The Synthesizer should be very modular. For Frequency change I want only to change the VCO and the filter. For the hole Band I want only one layout. The VCO is not the Problem the HMC5xx series can do all frequncys I want.
The filter is the Problem:
My solution is: To make a ground plane on the Top Layer of the Layout and solde an edge coupled filter on the top of the ground plane. The edge coupled filter is printed on an extra thin pcb with only 2 layer (1:Signal, 2:ground)
An extra circuit board with connector is to big.
Maybe someone has another grandios idea for changeable filter on circuit boards.
Thank a lot.
I think you will find that the low frequency filter will be around 7 times bigger than the highest frequency filter. I would design the filters first, and then figure out how to lay out the main board! You might want lumped element or ceramic resonator for the low frequency, combline for the mid frequency, and edge coupled for the highest, for instance.
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I think you will find that the low frequency filter will be around 7 times bigger than the highest frequency filter. I would design the filters first, and then figure out how to lay out the main board! You might want lumped element or ceramic resonator for the low frequency, combline for the mid frequency, and edge coupled for the highest, for instance.
Hi Biff44,
The Problem are not the low frequency for this I can use a Loow pass filter like LFCN-Filters from MC http://217.34.103.131/products/filters_sm_low.shtml.
But for the higher Frequency I need a frequency Multiplier an so I get a lot of Subahrmonics for 10GHz - 16 GHz I need the BP.
Sorry for the unclear description.
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Hi Biff44,
The Problem are not the low frequency for this I can use a Loow pass filter like LFCN-Filters from MC http://217.34.103.131/products/filters_sm_low.shtml.
But for the higher Frequency I need a frequency Multiplier an so I get a lot of Subahrmonics for 10GHz - 16 GHz I need the BP.
Sorry for the unclear description.
check hmc897 or similar tunable products which are bit expensive. you might need an extra AGC since the s21 of filters vary with center freq.
or you can find fixed band BPF`s @some mmic vendors such as gigoptix, etc.
or you can design filters for different frequency bands with similar layout.switch the lengths of transmisson lines with diodes; which is cheaper but harder way.
regards...
you can divide the band into several parts.
Use Mini-circuits until 8.4GHz. For higher band, i.e. 8.4GHz ~ 14GHzyou can use parallel line couple filter.
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you can divide the band into several parts.
Use Mini-circuits until 8.4GHz. For higher band, i.e. 8.4GHz ~ 14GHzyou can use parallel line couple filter.
You should use few interlaced BP filters and then you have to switch only one depending on your output frequency.
It's a general technique that is used in synthesizers/generators.
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You should use few interlaced BP filters and then you have to switch only one depending on your output frequency.
It's a general technique that is used in synthesizers/generators.
@kh4n
The HMC897 is not usefull for my application, the BW ist to big, the return loss to less and i can′t produce 14 V controll Voltage on my board.
The diode sultion is to complex to tunning for the produce.
@ bigBoss,tony_lth
On my circuit board I have no space for more than one filter. So I have to solde a new filter for every frequency on the board.
thanks a lot for all answers
@kh4n
I tried the diode solution in ads but this doesn′t work for this high Frequency an the big tunning Bandwith.
The Flatness of the Filter is really bad -5dB (16 GHz-16.40 GHz). If you use real Comonets the IL ist 10 dB.
You need to optimize the filter with AWR. I used to design filter with less than 1dB ripple up to 26GHz.