[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

A new method for measuring direction and amplitude of multipath reflected waves is proposed, which uses two antennas, one fixed at the center and the other circularly scanned.
In this method, the amplitude and phase difference of the received signals from two antennas are measured and these data are utilized to estimate the multipath reflected components using FFT (fast Fourier transform) technique. This method requires less measuring space to obtain the given resolution as compared with the previously known linearly scanned methods.
In this paper, the principle of the new method is described. A computational algorithm based on FFT technique is also presented and discussed in detail

View full abstract

Twin loop antennas are most widely used for UHF TV broadcasting. Previous researchers analyzed them by assuming a sinusoidal current distribution. Others adopted the higher order expansion (Fourier series) of the current distribution, however, their analysis did not sufficiently explain the wide-band characteristics of this antenna.
This paper applied the moment method to a twin loop antenna with a reflector plate or a wire screen-type reflector plate. As for the input impedance, 2L-type twin loop antenna has reactance nearest zero (in case that l₁=0.15λ0), that is, the VSWR is nearly equal to unity. Also, satisfactory wide-band characteristics were obtained. The agreement between the measurement and the theory is quite good.
It will thus be possible in future to improve practical antenna characteristics based on the obtained results.

View full abstract