Millimeter Wave Broadband Antenna in Package for 5G Communication

The millimeter-wave package antenna plays a crucial role in advancing 5G communication technology, enabling high-speed data transmission, low-latency communication, and increased connection density. This paper proposes a novel K-band wideband antenna in a package array based on a multi-layer dielectric substrate, The antenna array features a composite structure with three layers of dielectric substrate and four layers of metal. The chosen dielectric substrate is Rogers RO4350B with a relative permittivity of 3.66 and a loss tangent of 0.0037. The overall dimensions of the entire antenna are 36.6 × 6 × 0.97 mm³, with the dielectric substrate being 0.52 mm, 0.25 mm, and 0.2 mm in thickness. The metal layers adopted a 0.018 mm copper layer, resulting in a total antenna thickness of 0.97 mm. The first metal layer of the antenna functions as a parasitic patch with dimensions of 2.6 × 2.6 mm², located on the upper surface of the first dielectric substrate. To increase the impedance bandwidth, four symmetrical slots of 0.8 × 0.3 mm² are introduced on this parasitic patch. The second metal layer serves as the main radiating patch, also with dimensions of 2.6 × 2.6 mm², situated between the first and the second dielectric substrate. A mutual coupling effect occurs when the parasitic and main radiating patches are stacked, leading to an expansion of the operating bands. The third metal layer is designed as the metal ground for the antenna, positioned between the second and the third dielectric substrates, forming an ideal metal plane. The fourth metal layer constitutes the microstrip feedline, feeding the main radiating patch through metal vias. Simulations using full-wave software reveal that the −10 dB return loss bandwidth of the proposed antenna element is approximately 13.1% (23.28–26.56 GHz), with a peak gain of 5.71 dBi. Subsequently, based on the design of the antenna element, a 1 × 4 antenna array is constructed. The spacing between antenna elements is set to 7.32 mm (0.6λ). The feeding network employs quarter-wavelength impedance transformation by microstrip lines on the fourth metal layer. Ultimately, the −10 dB return loss bandwidth of the antenna array is about 12.2% (23.22–26.25 GHz), with a maximum peak gain of approximately 12.22 dBi. Simulation results demonstrate that the antenna array exhibits broadband characteristics in the millimeter wave band.