A Hybrid Integration Strategy for Compact, Broadband, and Highly Efficient Millimeter-Wave On-Chip Antennas

Abstract

A novel hybrid integration strategy for compact, broadband and highly efficient mmWave on-chip antennas is demonstrated by realizing a hybrid on-chip antenna, operating in the [27.5-29.5] GHz band. A cavity-backed stacked patch antenna is implemented on a 600 µm-thick silicon substrate by using airfilled substrate-integrated-waveguide technology. A hybrid onchip approach is adopted in which the antenna feed and an air-filled cavity are integrated on chip and the stacked patch configuration is implemented on a high frequency PCB laminate that supports the chip. A prototype of the hybrid on-chip antenna is validated, demonstrating an impedance bandwidth of 3.7 GHz. In free-space conditions, a boresight gain of 7.3 dBi and a front-to-back ratio of 20.3 dB at 28.5 GHz are achieved. Moreover, the antenna is fabricated using standard silicon fabrication techniques and features a total antenna efficiency above 90 % in the targeted frequency band of operation. The high performance, in combination with the compact antenna footprint of 0.49 λmin × 0.49 λmin, makes it an ideal building block to construct broadband antenna arrays with a broad steering range.

Cost-Effective High-Performance Air-Filled SIW Antenna Array for the Global 5G 26 GHz and 28 GHz Bands

“…AFSIW stacks inexpensive dual-layer PCB laminates and, by locally removing the substrate and realizing sidewalls by either edge plating [16] or rows of vias [13], [17], implements air-filled waveguides/cavities. [16], [18]- [22] propose low-cost high-performance micro-and mmWave AFSIW components, including antennas [16], [17], [23]- [25] and waveguide-fed slot arrays [26], [27]. While the latter exhibit ultra-high radiation efficiencies, they suffer from a large footprint and a narrow bandwidth, making them less suited for broadband mmWave adaptive beam steering systems [28].…”

Air-filled Substrate-Integrated Waveguide Technology for Broadband and Highly-Efficient Photonic-Enabled Antenna Systems

“…The AFSIW technology has become well-established in microwave and mmWave applications because of its ability to realize robust and high-performance components in low-cost substrates (eg. FR4, PLA and silicon) at a low fabrication cost by relying on either standard PCB, 3-Dprinting or silicon process technology [3,4,5]. As in this technology the electromagnetic (EM) fields are confined to air-filled metallized cavities, multiple strategic advantages arise for AFSIW-based photonic-enabled antenna systems.…”

“…However, the former typically suffers from poor antenna performance due to the unfavorable properties of silicon, while the latter suffers from increased interconnect losses. To alleviate these issues, a novel hybrid on-chip integration strategy is proposed in [5] and illustrated in Fig. 2.…”

“…As the hybrid on-chip antenna strategy shows great potential, the next step will consist of interfacing the antenna to an opto-electric front-end module by applying similar techniques as in Section 3. Thorough co-design between the antenna and the opto-electric interface (and ad- [8] 34.5 4.00 95.0 1.15 × 1.15 [9] 68.0 5.70 96.7 0.16 × 0.28 [5] 28.5 13.00 90.9 0 0 0. . .4 4 49 9 9 × × × 0 0 0. .…”

“…The second design maximizes power transfer by conjugate matching of the antenna [4], thereby omitting the area-consuming IMN and its corresponding losses. In addition, we will discuss the challenges related to photonic-enabled mmWave RAUs and how these can be tackled by relying on AFSIW on-chip antennas [5].…”