what type of resistor??

[david_edaboard]

Hello everybody, it's my first post in this forum. I have a question.
I'm working for a project of a reconfigurable antenna for mobile and I try to design a bias circuit that controlled a pin diode for the switching of antenna.I don't kwnon what kind of resistor I need to use. the working frequency is about 1-3 Ghz and the value of resistor is 100 ohms. Thanks for an answer.
David

 

[johnjoe]

Can you roughly post your circuit?

 

[david_edaboard]

This is the circuit


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I have to find resistor,inductance and capacitance...the port is the patch of the antenna

 

[madhusuthanan]

hi the RLC is used for the filter purpose.

 

[sina.parsnejad]

set capacitance and inductance to some values that you have already in hands. then set the resistor according to them.

 

[david_edaboard]

The problem is not in the value of the components but the model. can you show me some kind of datasheet? thanks a lot.

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The generator control the DC signal that switch the diode, the RF signal come from the port...the inductance block RF signal and the capacitance block the DC signal

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Help me please!

 

[tony_lth]

Panasonic has resistor model for simulation, for your case 0603 package is OK.

 

[fredd]

what simulator are you using? you can check first the database or library for all the resistor models.
and then check it online for its datasheet or technology kit manual.

 

[david_edaboard]

I'm using Microwave Office

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Does panasonic 0603 works at 3 Ghz? i have to realize the circuit in the reality but i don't kwon what type of component I need to use. the frequency range is 1-3 ghz

 

[rohitkhanna]

I'm using Microwave Office

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Does panasonic 0603 works at 3 Ghz? i have to realize the circuit in the reality but i don't kwon what type of component I need to use. the frequency range is 1-3 ghz

Are you actually talking about modeling the PIN diode's forward resistance Vs bias current ?!? My guess is that you are.

If so, then you should select an appropriate PIN diode for 1-3Ghz range and capable of 100ohm. Once you have selected the diode, then check the manufacturers website for an "model" which is compatible with your simulation software. Tho' I'm sure Microwave Office has the models built-in... surely ?

 

[david_edaboard]

Yes! the model of pin diode is in the library of MWO...I've used for this simulation a BAR64 Pin diode (Infineon)

 

[jeffrey samuel]

if model is available there is no prob just by viewing the op in the scope vary the resistor till you get a satisfied op

 

[biff44]

I assume there is a nother port, not shown, that leads to your transceiver?

290 nh is, of course, way too large for 1-3 GHz. It will resonate at a much lower frequency. Try something like a 12 nh...check the data sheet to make sure its series resonant frequency is higher than 3 ghz!

After the resistor, you need a capacitor to ground....maybe 22 pF. Keep the inductor, resistor, shunt 22 pf cap all very close together, and the inductor has to be close to the main line.

 

[jeffrey samuel]

my friend here needs the data sheet as mentioned in previous post

if you have be so kind to post it for the greater good

 

[rohitkhanna]

I assume there is a nother port, not shown, that leads to your transceiver?

290 nh is, of course, way too large for 1-3 GHz. It will resonate at a much lower frequency. Try something like a 12 nh...check the data sheet to make sure its series resonant frequency is higher than 3 ghz!

After the resistor, you need a capacitor to ground....maybe 22 pF. Keep the inductor, resistor, shunt 22 pf cap all very close together, and the inductor has to be close to the main line.

I don't think the inductor/ cap are there to form a resonant ckt. The Inductor is usually placed there as a choke to block the RF into the bias circuit part, and the cap is there to block the DC bias from getting into the RF stages. PIN diodes are usually used as RF switchs/ attenuators and such like. Though the poster has not stated the purposeof his circuit. Nor has he stated what HIS purpose is very clearly either. So we're all going round n round like a bunch of blind mice.

cheers!

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..... to post it for the greater good

Lmao !! :lol:

 

[david_edaboard]

Sorry! maybe I don't explain very well what's my problem.
- The values in the circuit figure are wrong. The figure represents only the circuit uder analysis (I have yet to find the exact values).
- The port represent a pin of a reconfigurable antenna (show in figure)

- for each pin in figure I have to realize the previous circuit that allows the reconfigurability (by pin diode)
- the inductance should block RF signal when diode is ON and the capacitance should block the DC signal when diode is OFF

My problem is to find the right component. In particular: resistor, inductance and capacitance. I don't kwon which datasheet to refer to. Approximately the value of R,L,C are R=100ohm, L=100nH, C=100pF. What do you think? Am I clear? Thanks

 

[madhusuthanan]

hi david,

if it is works fine means uts enough for this design.

 

[fredd]

Sorry! maybe I don't explain very well what's my problem.
- The values in the circuit figure are wrong. The figure represents only the circuit uder analysis (I have yet to find the exact values).
- The port represent a pin of a reconfigurable antenna (show in figure)

- for each pin in figure I have to realize the previous circuit that allows the reconfigurability (by pin diode)
- the inductance should block RF signal when diode is ON and the capacitance should block the DC signal when diode is OFF

My problem is to find the right component. In particular: resistor, inductance and capacitance. I don't kwon which datasheet to refer to. Approximately the value of R,L,C are R=100ohm, L=100nH, C=100pF. What do you think? Am I clear? Thanks

Hi david,

I think the first thing you must do here is to model your design using ideal RLC and making your design work at 1-3GHz.
L=100nH is too large to start with. You can start with lower L like 1nH or 5nH and then do a parametric analysis for determining the value of C (example, sweep C from 0.5pF to 5pF with 0.1pF step).
After achieving the desired frequency of operation, this is the time where you'll consider the right RLC components for your design. At least this time, you have now a working circuit using ideal components.