An 18 GHz circularly polarised multilayer active microstrip antenna subarray using MMIC amplifiers

The paper presents an 18 GHz circularly polarised multilayer active antenna subarray using MMIC amplifiers. With the advantage of a multilayer structure, the radiation patterns from the antenna side are not affected by the radiation from circuit side. An extra gain of 15.46 dB has been measured in comparison to the passive array. This type of array can be the ideal building block for large microstrip phased array systems.