[Prev][Next][Index][Thread]

Re: MOSFET Coil Paper (antenna input impedances)



>> His essential conclusion is that before breakout the the input impedence
is
>> close to that of a quarter-wave antenna. I'm not a radio type so is there
a
>> general equation giving the inpit inpedance of a quater wave antenna.


Quarter wave antennas ( I assume you mean a monopole over a ground plane) at
resonance have an impedance of 36 ohms resistive (at resonance is the key).
it gets tricky when the antenna is real (i.e. lossy components of finite
size over a finite lossy ground, etc.)  But, there are some equations giving
the impedance of an arbitrary cylindrical or conical size.

TC's are so small in wavelengths (100 kHz wavelength = 3 km) that antenna
formulae wouldn't be really applicable.