Most antennas operating at millimeter wave frequency use mechanical scanning or phase shifters, both of which have disadvantages. Mechanically steered antennas are slow in response and suffer reliability problems from shock and vibration.
Phase shifters are costly to fabricate and introduce considerable RF losses.
Accuracy requirements force them to be large, precision made and expensive. By avoiding these drawbacks, the Rotman lens antenna could open new applications for millimeter wave radar. This invention has no moving parts, no phase shifters and can be implemented in plastic. It is reliable, compact and inexpensive. It is also the first Rotman lens to be produced at 35 GHz or above.