Beam scanning capability and suppression of endfire radiation of dipole array antennas coupled to two-wire parallel transmission line

Abstract

In this letter, radiation pattern of a dipole array antenna coupled to a two-wire transmission line is numerically investigated. The effect of array spacing on the main beam direction of the array antenna is shown. In addition, it is shown that the endfire radiation of the array antenna can be suppressed when series inductors are loaded with the two-wire transmission line.

Continuous beam scanning performance of dipole array antenna coupled to meander two-wire parallel transmission line

“…According to [9], the proposed antenna has a grating lobe and inductors should be loaded with the transmission line in order to suppress the grating lobe. However, in the millimeter wave frequency band, it is difficult to deal with an inductor as a lumped element because its dimension is comparable to the wavelength.…”

“…On the other hand, a mechanical beam scanning dipole array antenna coupled to two-wire parallel transmission line has been proposed and its beam scanning performance was demonstrated [8,9]. The proposed antenna is a kind of a leaky-wave antenna and all array elements are excited via the near-field of the two-wire parallel transmission line.…”

“…Beam scanning capability of the proposed antenna comes from variable array spacing which is available using an actuator. In [9], it was demonstrated that a couple of inductors loaded with the transmission line can suppress its grating lobe. The inductors are modeled as lumped elements in [9] while the size of inductors is comparable to wavelength in millimeter-wave band.…”