cooleyn said:How wide bandwidth do u want to achieve for the matching? and the S11? For achieving above 10% band width bandpass filter maybe need for the matching..
Since R is so small, it's hard to do matching..
cooleyn said:You could refer to some filter design/synthesis book. You have to put L and C as part of bandpass filter.Since R is so small(Q valueis high), I think it's difficult.If you accept loss matching, it becomes more easy. What're the specific values for L and C?
Element_115 said:Can you put elements in parallel with the filter?
Or add a resistor in series? More BW and more
passband attenuation.
First plot you Filter out on a Smith chart then put
Q lines on the Smith Chart and add components that
1) keeps the impedance in the Low Q region and that
will bring your filter to a Zo match.
Yes, I know that it can be vey difficult. L is 35 nH, and C is 0.1 pF. The problem is that we can't seperate L and C from the block.
VSWR said:Yes, I know that it can be vey difficult. L is 35 nH, and C is 0.1 pF. The problem is that we can't seperate L and C from the block.
L = 35 nH, C = 0.1 pF, R = 5 ohms does not resonate at 915 MHz. Resonance is at 2690 MHz.
derek_lkm said:Hi all,
Find this topic interesting, however i not really sure why the matching is diffcult. From my basic understanding, it would just be made with the movement on the smith chart and its corresponding passive values. I understand that for maximum voltage transfer, we would like a large load, but since we are mentioning about Sparameters, we are interested in power transfer. As long as the matching is done up we should get the maximum power transfer. Maybe i'm wrong or i have taken enough factors into considerations? Would like to hear the views of the gurus out there.
Thanks and wish everyone have a nice day.
Regards
Derek
ND said:What type of circuit you are using?
If it is for example microstrip you my try design some matching network using transformer lines, rather then discreet elements.
ND said:By my opinion, it is easier and cheaper (especially on higher freq.).
In your case is even more distinctive, because you will need to use elements with very high Q, although your are design circuit on very high freq.
Jim cage said:you can try and use double L-matching network or even triple L-matching network. this will result in lower Q and thus bigger bandwidth
MW+RF=Netpig said:it just like a case about DVB-S which the broadband 915MHZ--2150MHz
Added after 3 minutes:
you can simulate it with agilent ADS which include the tuning function you can get the values you need ,it's important to pay attention to the RF PCB layout. for broadband matching ,i think the PI network is the best ,you can use 2rd PI network
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