Rotman lens has been used to achieve low cost, reliable, multibeam phased arrays. However, the Rotman lens is not an efficient power dividing component because losses of nearly 3 dB may be attributed to the non-perfect focusing of the rays within the lens. In the ideal situation, all power emanating from a particular beam port would be divided and coupled to each array port. However, in reality, a substantial amount of power is distributed throughout the lens and not focused upon the array ports. Substantial power losses, in fact, occur via the sides of the Rotman lens, which have been terminated to reduce unwanted reflections and minimize phase errors at the array ports.
Researchers at University of Michigan have developed a new low loss Rotman lens implementation. With the introduction of dielectric contours of varying permittivity within lens, enhanced focusing of the RF power onto the array ports is achieved with minimal power loss to the absorbing ports.
Applications and Advantages
- Imaging systems
- Automotive collision avoidance radar
- Remote sensing
- Multiple-input-multiple-output (MIMO) communication systems
- Low power loss
- Broadband multi beam capabilities