Broadband X-Band LTCC Front-End Prototype Integrated With Air-Cavities-Embedded Antenna-in-Package

A wideband front-end module with antenna-in-package (AiP) for X-band phased-array radar applications is newly presented using low-temperature co-fired ceramic (LTCC) technology. This work integrates multiple chips into the AiP, resulting in a multifunctional front-end prototype. For improving antenna bandwidth and radiation efficiency, four air cavities are embedded inside the package to lower the effective dielectric constant. Additionally, bowtie-shaped patches and improved apertures are introduced to increase the antenna bandwidth further. The overall size of the LTCC package is 14.3 × 24.5 × 3.55 mm³. The antenna's voltage standing wave ratio is better than 2.5 at the full X-band (40% bandwidth), and the maximum gain is 8 dBi. Besides, the receive gain of the active prototype is better than 30 dB at the full X-band, and the transmit equivalent isotropic radiated power is 32–38.5 dBm, showing a good performance.