STUDY OF CHANGES OF ROTMAN LENS GEOMETRY FOR PLACING ON MOBILE CARRIERS
The paper investigates the influence of the change in the geometry of the Rotman strip lens on its performance. Rotman lens (sometimes called the Rotman-Turner lens) is a type of diagram-forming scheme. This lens allows you to form multiple antenna beams without using switches or phase shifters. Antenna elements are connected to one of the end sides of the lens, while the ports of the rays are on the opposite side. You can imagine a lens as a quasi-microstrip (or quasi-strip) scheme, where the location of the ports of the rays is chosen so as to achieve constant phase shifts on the ports of the antenna elements. When antenna elements are powered by linearly varying phases, the device behaves exactly like a phased array. One of the remarkable properties of this lens is that, despite the presence of multiple ports of 50 Ohms, they remain isolated, and therefore do not affect the loss (or noise) of adjacent rays. A well-designed Rotman lens can have a loss of just 1 dB. Since the structure is more like a plane-parallel waveguide than a transmission line, linear antenna modeling programs are not suitable, and you have to use numerical methods that Rothman himself used, or powerful software systems. As a result of the field experiment, we obtained the matching characteristics for the original and transformed lenses, which are compared with the design parameters of the antenna