Help me design a RF Surge Arrester
please help me in designing a RF SURGE ARRESTER. any information on this helps me a lot....
specifications:
Bandwidth 800-900MHz
Impedance: 50 Ω
Return loss: > 20dB
Insertion loss : <0.2dB
thank you
How big of a surge?
Rich
Hi,
withstanding voltage AC (V min) ≥ 4000 volts
Discharge voltage (origination) in volts is 75/90/150/230
bandwidth for surge arrestor1: DC-2500MHz
surge arrestor2 : 1572.42MHz
how do i start designing this?
thanking in advance
Chandre gowda H
Your specs are a little confusing to me. But basically, there are two standard ways to stop surges:
1) have a quarterwave shunt line with a short circuit at the end. This provides an RF open circuit to the thru path, but is a dead short circuit to any other frequencies. The problem is that this can be narrowband, as far as the low loss passbandwidth.
2) use a circuit protection device. These are common for stopping lightning strikes from damaging equipment, put in shunt across the input:
http://www.littelfuse.com/data/en/Da...GDT_CG-CG2.pdf
Because of the low capacitance, they do not impede most RF signals. You do have to design in a low resistance return path to earth ground.
You can clean up any pulse leakage with a diode limiter following this.
Rich
hi,
The electrical specifications:
Lighning Arrestor1
Frequency: DC-2500MHz
Impedance: 50 ohms
Inner contact resistance: ≤ 0.4m Ohm
Outer contact resistance: ≤ 0.2m Ohm
Insulation resistance : ≥ (1 x 10E+4) M Ohm
Insertion : ≤ 0.5dB
Withstanding voltage AC (V min) : ≥4000v
VSWR : ≤ 1.15
Power : 200watts
Discharge voltage (origination) (V) : 75/90/150/230
Durability : 500 Cycles
Termination : N female
Mechanical specs- Weight: 125 Gms
Environmental specifications - Temp: 0 degree C - +60 degree C
Shell Safety Rate : IP 68
Lighning Arrestor2
Frequency : 1575.42MHz
Remaining are Same specifications.
Thank you
Gee, you think you would at least aknowledge the free advice Rich is giving you?
I have you the gas discharge tubes (GDT) Rich is referring to, you should check them out.
Rod
hi
do u got the design concepts?
i have same query
pls write me to birarimahesh@gmail.com
2
As far as I'm aware of, only quarter-wave stubs achieve the said insertion loss specification. They are comercially
available from major companies, e.g. telegaertner.com or hubersuhner.ch.
Here is a pic of a typical surge arrestor:
http://www.rfshop.co.uk/lightning-pr...protector.html
They are made from a short 50 ohm airline which ensures low loss and a Gas discharge tube which looks like:
http://img.alibaba.com/photo/5119040...harge_tube.jpg
This contacts between the centre conductor of the airline and the outer ground. They can be chosen to fire at different voltages.[/url]