Modulation helps to reduce the antenna size in wireless communication-Explain.

Explanation

Anteena size:
Anteena is used at both transmiter and receiver end.Anteena height is an important parameter to be discussed.The height of the anteena must be a muliple of `(lambda)/4`
`h=(lambda)/4`
Where `lambda` is wavelength `(lambda=c/v)`,c is the velocity of light and v is the frequency of the signeal to be transmitted.
An example
Let us consider two baseband signal is modulated the frequency of the original baseband signual is taken as v=10 kHz while the modulated signal is v=1 MHz.The height of the antenna to transmit the original baseband signal is v=1 MHz the height of the antenna required to transmit the original baseband signal of frequency V=10 kHz is
`h_1=lambda/4=c/(4v)=(3xx10^(8))/(4xx1xx10^(3))=7.5 km`
The height of the antenna required to transmit the modulated signal of frequency v=1 MHz is `h_2=lambda/4=c/(4v)=(3xx10^(8))/(4xx1xx10^(6))=75 km`
Comparing equations (2) and (3),we can infer that it is practically feasible to constrauct an antenna of height 75 m while the one with 7.5 km is not possible.it clearly manifests that modulated signals reduce the antenna height and are required for long distance transmission.