A rectangular aperture antenna with a tilted beam

For some antenna applications, for example, mobile communications, there is a requirement for the antenna to radiate a tilted beam. Previous investigation has shown that the beam tilt angle can be varied for a square aperture antenna constructed using a triplate transmission line (TTL) by changing the side length of the square aperture. However, an increased side length is undesirable when constructing an array antenna of square apertures, because the increased side length makes the distance between the aperture elements large and thus gives rise to undesired grating lobes. One way to avoid this drawback is to use a different aperture shape. This paper presents a rectangular aperture antenna constructed using the TTL structure. The main purpose is to form a beam tilted from the direction normal to the antenna plane. The radiation characteristics of the rectangular aperture antenna are presented and discussed.