Patent ID: 8451720

Claim:
A wireless transmission system, comprising: a plurality of antenna pairs each formed from a combination of a transmission antenna and a reception antenna which correspond to each other and arranged such that a wireless signal transmitted from the transmission antenna of one of the plural antenna pairs directly arrives as a desired wave at the reception antenna of the one antenna pair and a wireless signal transmitted from the transmission antenna of a different one of the plural antenna pairs different from the one antenna pair directly arrives as an unnecessary wave at the reception antenna of the one antenna pair; a demodulation functional unit provided corresponding to each of the antenna pairs for demodulating a modulation signal received by the reception antenna; and a transmission characteristic correction unit for carrying out correction calculation based on a transmission characteristic of a transmission space between the transmission antennae and the reception antennae based on demodulation signals demodulated by the demodulation functional units corresponding to the reception antennae to acquire an output signal corresponding to a transmission subject signal, wherein path differences each of which is a difference between an inter-antenna distance of the desired wave and an inter-antenna distance of the unnecessary wave between the transmission and reception antennae is set such that each of elements of the desired wave of a matrix which defines the transmission characteristic can be represented only by a real number term while each of elements of the unnecessary wave of the matrix which defines the transmission characteristic can be represented only by a real number term or only by an imaginary number term, and wherein, where a wavelength of a carrier signal used in said demodulation functional unit is represented by λc and a phase characteristic which relies upon directivity of an antenna is represented by zero, the path difference which is a difference between the inter-antenna distance of the desired wave and the inter-antenna distance of the unnecessary wave between the transmission antenna and the reception antenna is set to (n/2+¼)λc, n being 0 or a positive integer equal to or higher than 1; or, where a radiation angle from the transmission antenna to the reception antenna of the one antenna pair is represented by θ 1 and another radiation angle from the transmission antenna of the different one antenna pair to the reception antenna of the one antenna pair is represented by θ 2 , and phase characteristics which rely upon the directivity of the individual antennae are represented by φa(θ 1 ) and φa(θ 2 ), the path difference is corrected by −(φa(θ 2 )−(φa(θ 1 ))/π)λc.