Wavelength

Stride of diffraction parallelize bandwidth

Above pictorialize is the time of one of diffraction length, ---- one light-second can run 30 MyriaKM

wavelength = diffraction/frequency Assumedly, when we design for a 863.5MHz antenna,£f(wavelength)/4(antenna) then (3/8.635)/4=0.089M=8.9CM
The antenna can be putted into the buttom of inductance to supply wavelength, if the length of antenna impermissible to long

supply wavelength Communicated loss

Radio wave communicated in outer space, owing to increasing distance, receive to field strength will inverse ratio, The account formula as following:
receiving field strength Wr transmiting field strength Wt, frequency f (Hz), distance d (m), wavelength (m), transmite Gt , receive Gr

Example: discriminate 400 MHz, distance 500m

length of the λ/2-dipole antenna is given by L = 14250 / f ,
IF IS 900MHz the aerial length is 14250/900=15.83cm length of the λ/4-dipole antenna is given by L = 7125 /F,
IF IS 900MHz the aerial length is 7125/900=7.91cm