Inductor and RF Choke at 5.25 & 35.5 GHz
I am looking for an inductor and RF Choke at 5.25 & 35.5GHz. Does anyone know where I can buy it from?
Thanks in advance
Your request is a bit confusing.
A typical choke coil for RF application should have a significantly higher reactance than the nominal line impedance, e.g. 50 Ohms. The best RF choke is made by winding a quarter-wavelength long wire on a cylindrical carrier.
Wire thickness should be as small as possible- but now you have to compromise with the DC current you need to pass through the choke.
At 5.25 GHz, the wavelength is 5.7 cm, so if you take a piece of 0.3 mm dia. wire 1.42 cm long and wind it on a 3-4 mm pin to form a coil, you have a good choke. Wire 0.3 mm thick can carry 0.25 A DC.
At 35.5 GHz things are not so easy; a coil made like the above will not work. Instead, use a quarter-wavelength section of a 0.085" diameter semirigid coaxial cable. This will work as a good "choke", you would find that you should make it a bit shorter than 2.1 mm (quarter wavelength) and tune it with a side screw. I would use a similar short "pad" and tune it with a shorting plug for the best performance.
In MMIC application at 35 GHz and even higher, there are "conical" chokes available but typically a thin wire is used like 0.1 mm, so DC current is limited. Such conical choke starts with ~2 mm diameter and ends with <0.5 mm diameter- the arrangement works well up to ~50 GHz.
Added after 3 minutes:
Still to add something: you also asked for a RF coil design; for your frequencies, coils are NOT used. Their stray capacitances would render any coil unusable.
Sections of coaxial lines or waveguides are used instead.
Please read a good textbook on microwave technology; a good information can be found e.g. in the ARRL Radio Amateur Handbook issued annually by ARRL.