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