LTCC Differential-Fed Broadband High-Gain and Narrow-Beam Planar Aperture Antenna for AiP Millimeter-Wave-Applications

The article presents a differentially excited low temperature co-fired ceramics (LTCC) based miniaturized planar aperture antenna, distinguished for its high gain and narrow-beam wideband characteristics, tailored specifically for mm-Wave antenna-in-package (AiP) applications. The proposed antenna comprises a stepped-cut patch element excited differentially and enclosed within an open cavity formed by metallized vias. Four tuning stubs are symmetrically incorporated into the stepped-cut patch element, and two pairs of shorting vias are used to ground it, improving overall impedance and gain bandwidth. Rectangular-shaped parasitic strips, strategically positioned outside the open cavity in a symmetrical arrangement, significantly narrow the main beam along two principal cutting planes, thereby enhancing broadside gain across the entire frequency band of operation. To validate the proposed design, a miniaturized and low loss differential feeding network was designed using the same LTCC technology and seamlessly integrated into the underside of the prototype antenna. According to measured results, the fabricated prototype exhibit −10 dB impedance bandwidth of 20.97% (56.55–69.8 GHz), and the realized gain is higher than 10.01 dBi with a peak gain of 12.36 dBi at 63 GHz. Moreover, the radiation pattern of the proposed design is perfectly symmetrical, boasting a half-power beamwidth less than 40° along both the planes across the entire operating band.