Design and Simulation of a Power Efficient Waveguide Rotman Lens

Rotman lens is a true-time-delay beam forming network with parallel plate structure. Owing to its frequency- independency and wide-band operation, it has gained vast applications as feeding element of linear array antennas. However, the lens suffers from high intrinsic power loss and the problem worsens in microstrip structures by their inevitable dielectric loss. On the other hand, waveguides experience extremely lower loss and also have higher power capacity. Thus, waveguides can be advantageously utilized in Rotman lens structure. Here, a waveguide Rotman lens for the frequency range of 8 to 12 GHz is designed and simulated in CST Microwave Studio. Phase error and power efficiency of the proposed structure are satisfactory.