uhf germanium diode rf probe

We wish to make 75 ohm RF detector for testing VHF-UHF small signal amplifiers. Pl. guide me in the matter.

Hi,

You can use some simple diode detector, or some integrated solution like AD 8314 from Analog Devices
If you need some schematic, send me a PM.

rgds, Al

AD 8314 starts from 100 mhz. we need from 20 ~1000 mhz. Kindly suggest diodes. What diodes r used in the commercially available detectors?

sum info about rf probe .
http://www.seits.org/features/rfprobe.htm

On the:
hxxp://www.dl5neg.de/index.html
You can find well documented article about how to make power sensor (diode detector).

We hv came across few diodes.
BAT 17 & BAT 62 nice but hard to get. We think BAT 62 is better, Kindly comment.
1N34A is old germanium diode. Can i use it for the time being i get other diodes or it will also serve my purpose.

You may use 1N34 but measuring result will be reduced at higher frequencies above 100MHz up to 1GHz. Diode is point contact diode and was intended for usage at lower frequencies, I think.

The BAT62-02W isn't hard to get. Infineon has a worldwide network of distributors. See

http://www.infineon.com/cgi/ecrm.dll...&cat_oid=-8974

You just have to call any of them to get a few samples.

The DL5NEG's detector design is very nice and should fit your needs.

Thanks! There is 50 ohm stripline. I want to use it for 75 ohm. Guide me what & how to change it to 75 ohms stripline. Other values i can change except the layout stripline.
MP

I think there is microstrip not stripline.
Here you can download transmission line calculator: http://www.appwave.com/products/txline.html

Some parametars in circuit need to be changed, resistors, capacitors because you have not 50 ohm input impedance and the same fraquency range.

Try to use any circuit simulator to check this.

Thanks for the support. Dut to this i got it done with Japanese Schottky diode lying with me. It was nice with .9 pf jc at 1 Mhz. I got the diode very chip just for 10 cents in wholesale.