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The increasing capabilities of high‐speed silicon technologies have made millimeter‐wave frequencies attractive for low‐cost applications. This chapter focuses on large‐array antenna‐in‐package (AiP) designs based on surface laminar circuit (SLC) technology at 28 and 94 GHz. It investigates antenna designs considering both manufacturability and the general performance requirements and presents a 30.5‐GHz antenna design and associated characterization results. The antenna design is based on SLC technology and supports both horizontal and vertical polarizations to enable realization of a large phased‐array module with multiple simultaneous beams for 5G applications. The chapter provides information on the AiP portion of the first reported SiGe‐based scalable phased‐array module to illustrate the challenges and initial solutions. Millimeter‐wave scaled phased arrays support many antenna elements. Phased‐array scaling is advantageous because it provides a path for supporting antenna arrays with a larger number of elements than a single integrated circuit can support.

The twenty peer-reviewed letters in this special section examine the design and cointegration of antenna-in-package (AiP), antenna-on-chip (AoC), and antenna ICs (AIC). The letters are categorized in the four distinctive categories: 1) Fabrication technologies (four); 2) Measurement strategies; 3) Applications; and 4) New design and integration strategies. Fruition of major thrusts such as 5G/6G, high-resolution radar and imaging, autonomous driving, and space technology are highly intertwined with the advance of applied electromagnetics. Miniaturization and seamless integration of microwave components and radio systems can enable superior performance, form factor, and cost efficiencies leading to enhanced proliferation of such applications. Historically, radio frequency front ends, antennas, and microwave components have separately evolved using distinct fabrication and measurement technologies.

Silicon-based millimeter-wave (mm-wave) phased-array technologies are enabling directional wireless data communications at Gb/s speeds. In this paper, we review and discuss the challenges of implementing a multichip phased-array antenna module for mm-wave applications using organic buildup substrate technology. A prototype test vehicle has been fabricated and studied to evaluate the antenna and interconnect performance, dielectric properties, package substrate warpage conditions at different temperatures, chip- and board-level joint process reliability, and thermal management feasibility for cooling. Based on the learning from the test vehicle, an organic-based multilayered phased-array antenna package for 28-GHz mm-wave radio access applications is implemented. The package incorporates 64 dual-polarized antenna elements and features an air cavity common to all antennas. Direct probing measurements on a single-antenna element of the package show over 3 GHz of bandwidth and 3-dBi gain at 28 GHz. A phased-array transceiver module has been developed with the package; the module includes four SiGe BiCMOS ICs attached using flip-chip assembly. Module-level measurements in the TX mode show a 35-dB near-ideal output power increase for 64-element power combining; 64-element radiation pattern measurements are reported with a steering range of ± 50° without tapering in off-boresight directions, and 64-element radiation pattern measurements with tapering show achievement of a sidelobe level lower than −20 dB. The transceiver modules achieved 20.64-Gb/s throughput with 256 QAM and 800-MHz bandwidth in direct over-the-air link measurement results.

This paper presents novel antenna designs and integration methods that enable a low-cost scalable antenna-in-package (AiP) phased-array solution for wideband wireless communication covering 24 GHz - 30 GHz (N257, N258 and N261 5G bands). A total number of 26 dual-polarized antenna variants based on two implementation approaches were fabricated on a $\mathrm{47.5}\text{mm}\times \mathrm{47.5}\text{mm}$ package test vehicle with an element-to-element pitch of 5.9 mm. The first approach consists of integrating a magneto-electric dipole antenna array in a single laminate and the second approach consists of an aperture-coupled patch antenna array implemented in a superstrate forming a 2-laminate structure. Passive measurement results demonstrate the feasibility of achieving more than 5GHz input return loss bandwidth and 7dBi peak antenna gain with over 20dB cross-polarization isolation at 28 GHz, as well as near-identical radiation patterns for both H and V polarizations. In addition, the AiP test vehicle contains two $\mathrm{4}\times \mathrm{4}$ antenna arrays (one for each design approach) that support integration with 28-GHz SiGe phased array RFICs for active testing. Over-the-air active module measurement results are reported, including near-ideal spatial power combining, antenna gain uniformity across elements within +/-2.5dB, as well as 16-element beam-forming and beam-steering in a ±60° range.

In this article, we present a low-power, small form-factor, 60-GHz packaged radio featuring broad beam coverage. We increase angular coverage by beam switching between two orthogonally pointed low directivity beams that are created using two different antennas integrated in package. The resulting wide angular coverage of the radio makes radio links robust to movement and rotation; this improvement overcomes a key challenge for millimeter-wave (mmWave) deployment in portable electronics. We incorporate a 3.2 mm $\times $ 3.2 mm 32-nm CMOS radio integrated circuit (IC) in the package for radio functions. The IC includes TX and RX RF front ends, up- and down-conversion mixers, TX and RX analog baseband circuits, a common PLL, TX and RX LO chains, and ADCs and a micro-controller for built-in self-test (BIST). The IC is flip-chip packaged on a four-layer organic package comprising two TX antennas and two RX antennas. In board-level over-the-air measurements of the half-duplex packaged radio, 17.1-dBm effective isotropic radiated power (EIRP) and 6.1-dB noise figure are achieved in the TX and RX modes respectively, with power consumption below 250 mW in either mode. We characterized the radio over the air using 802.11ad waveforms; the radio is 802.11ad compliant in both TX and RX modes at data rates up to the maximum 802.11ad PHY rate of 4.62 Gb/s (raw data rate >7 Gb/s) with a TX EVM $\pi $ steradians in first-of-a-kind measurements. The radio maintains 802.11ad compliance over 2.9 $\pi $ steradians solid angle.

This paper presents the first reported 28-GHz phased-array IC for 5G communications. Implemented in 130-nm SiGe BiCMOS, the IC includes 32 TRX elements and features concurrent independent beams in two polarizations in either TX or RX operation. Circuit techniques to enable precise beam steering, orthogonal phase and amplitude control at each front end, and independent tapering and beam steering at the array level are presented. A TX/RX switch design is introduced which minimizes TX path loss resulting in 13.5 dBm/16 dBm Op1dB/Psat per front end with >20% peak power added efficiency of the power amplifier (including switch and off-mode LNA) while maintaining a 6 dB noise figure in the low noise amplifier (including switch and off-mode PA). Comprehensive on-wafer measurement results for the IC across multiple samples and temperature variation are presented. A package with four ICs and 64 dual-polarized antennas provides eight 16-element or two 64-element concurrent beams with 1.4°/step beam steering (

Fifth-generation wireless technology, denoted as “5G” by the global wireless communications industry, seeks to accomplish multi-fold increases in key aspects of wireless communication. In conjunction with conventional microwave frequencies, millimeter-wave (mmWave) and THz frequencies and technologies are being investigated by major research institutions and industry. Deliberations are underway by regulatory officials around the world to authorize mmWave and sub-THz spectrum for 5G fixed and mobile applications. In the development of 5G communication systems, new propagation phenomena, novel multi-antenna transmitting architectures, and new mmWave operating frequency bands using much wider channel bandwidths than ever before are proving to be extremely effective ways to dramatically increase the communication data rate of future mobile communication networks. The papers in this special issue offer extensive insights and promising results that address many of the technical challenges that must be solved to usher in the 5G era.

Phased-array modules at frequencies >20 GHz are expected to play an important role for 5G applications. Antenna-in-package (AiP) is a reliable and cost-effective method to realize these phased arrays. This paper introduces a practical Ka-band AiP structure and discusses the antenna element design and implementation tradeoffs. The AiP design is based on multilayer organic buildup substrates that are suitable for phased-array module integration needs and supports both horizontal and vertical polarizations. Measurement results from the fabricated antenna prototypes show 0.8 GHz return loss bandwidth and 3.8-dBi peak gain at 30.5 GHz. Simulation results agree with the measured ones.

The 2020 award was presented to Yueping Zhang and Duixian Liu “For pioneering and significant contributions to the development of antenna-in-package (AiP) technology.”

This paper presents an aperture-coupled dual-polarized stacked patch antenna integrated in an RFIC package environment for Ka-band applications. The package is based on multilayer organic technology, so it can be fabricated by PCB manufacturers. The antenna has a measured peak gain > 5 dBi and supports a 4 GHz bandwidth.

Compact phased array transmitter (TX) and receiver (RX) modules operating at 94 GHz are presented and demonstrated in a 3D radar imaging system. Each module consists of four SiGe ICs and a package that integrates 8X8 dual-polarized antennas and 10-GHz IF power combiners. Each TX and RX IC integrates beam-forming, frequency conversion, LO generation, and digital control functions. The modules have beam steering capabilities in both azimuth and elevation over a range of +/- 32 degrees. A radar imaging system is implemented comprising an evaluation board with one TX module and one RX module, FMCW signal generation and acquisition components, and an FPGA for fast beam steering control. The system can steer TX and RX beams to a given direction and perform a radar measurement in that direction in less than 100us, enabling 3D imaging in real time. Measurement results are presented for the modules and the prototype imaging system.

This paper has shown that, by simply inserting a matching line, the probe pad effects on antenna impedance matching and frequency shift can be reduced. Simulation and measurement results confirm the method.

An organic-based multi-layered phased-array antenna package for 94-GHz radar imaging and communication applications is hereby introduced. The package incorporates 64 dual-polarized antenna elements. Direct antenna probing measurements on a fabricated package and full-wave electromagnetic (EM) simulation of the complete design show over 8 GHz bandwidth and 2 dBi gain at 94 GHz. 64-element beam forming and beam steering are evaluated through EM simulations showing 12-degree half-power beam width and lower than -20dB side levels. A novel flip-chip assembly process is introduced to improve module-level yield and scalability by attaching the package with one die that consists of four joint ICs.

Co-design and integration of RFIC, package, and antennas are critical to enable 5G wireless communications and is particularly challenging at mmWave frequencies. This paper reviews two different aspects of mmWave antenna module packaging and integration for base station and user equipment applications, respectively. We first present the challenges, implementation, and characterization of a 28­GHz phased-array module with 64 dual polarized antennas for 5G base station applications. Next, we describe a compact, low-power, 60-GHz switched-beam transceiver module suitable for handset integration incorporating 4 antennas that supports both normal and end-fire directions for a wide link spatial coverage.

Directional communication at millimeter-wave (mmWave) frequencies is one of the key technologies under development towards the anticipated deployment of fifth generation mobile access (5G). Silicon-based multi-antenna systems are strong candidates for the implementation of such directional links; however, the performance requirements are in general significantly more challenging than those posed by mmWave WLAN links demonstrated so far (e.g. for 802.11ad). This work presents an overview of recent innovations in circuit design, antenna design, and beamforming architecture which enable complex phased arrays with precise and agile beamforming for mmWave-based 5G communications. Specifically, this work discusses: (1) a 28-GHz phase shifting transceiver front end, (2) beamforming architecture considerations to enable dual polarized operation as well as multi beam configurability, and (3) two different 28-GHz antenna-in-package (AiP) designs. These advances have been jointly demonstrated in a 64-element dual polarized phased array antenna module (PAAM) consisting of four SiGe ICs and an AiP array. The PAAM supports two simultaneous and independent 64-element beams in either TX or RX modes. PAAM-level measurement results over the air without calibration show +/− 50° beam scanning with >10dB silde-lobe rejection

An organic-based multi-layered phased-array antenna package for a 28GHz 5G radio access applications is hereby introduced. The package incorporates 64 dual-polarized antenna elements and features an air cavity common to all antennas. Direct antenna probing measurements of the package show over 3GHz bandwidth and 3dBi gain at 28GHz. A phased array transceiver module has been developed with the package and four SiGe BiCMOS ICs are attached using flip-chip assembly. Module-level measurements in TX mode show 54dBm EIRP and near-ideal 35dB gain increase for 64-element power combining. 64-element radiation pattern measurements are reported with a steering range of > ±40 degrees without tapering in off-boresight direction.

The 43 papers in this special issue provide an overview of recent advances and emerging applications in millimeter and sub-millimeter waves, especially beyond 60 GHz up to terahertz, with strong focus towards practical implementable solutions.

This paper presents issues and practical solutions for SIW designs with very thin substrate with high profile metal roughness at mmWave frequencies.

A low power, small form-factor, 60-GHz radio with beam switching capability is presented. The 3mm×3mm radio IC in 32nm SOI CMOS includes the TX and RX RF front ends, mixers, basebands, PLL and LO chains. The package comprises 2 TX antennas and 2 RX antennas producing low directivity beams in two orthogonal directions to maximize spatial coverage, with an achieved angular coverage of 254°. In board level measurements of the half duplex packaged radio, 17.1dBm EIRP and 6.1dB noise figure are achieved, with power consumption below 250mW.

This paper presents the design of a fully packaged 60 GHz wideband patch antenna incorporating an air cavity and a fused silica superstrate. Circular polarization (CP) is realized by introducing a diagonal slot at the center of the square patch. By optimizing the patch and the slot dimensions, a high efficiency (>90%) microstrip fed CP antenna with an impedance bandwidth of 24% and a 6 dB axial ratio bandwidth of 21.5% is designed. A coplanar waveguide (CPW) to microstrip transition with λ/4-open-ended stubs are then designed to match the antenna to the CPW packaging interface. The experimental results of the final packaged antenna agree reasonably with the simulation results, demonstrating an impedance bandwidth of more than 26% and a 6 dB axial ratio bandwidth of 22.7%.

A multilayer organic package with embedded 60-GHz antennas and fully integrated with a 60-GHz phased-array transmitter or receiver chip is demonstrated. The package includes sixteen phased-array antennas, an open cavity for housing the flip-chip attached RF chip, and interconnects operating at DC-66 GHz. The 28 mm 28 mm ball grid array package is manufactured using printed circuit board processes and uses a combination of liquid-crystal polymer and glass-reinforced laminates, allowing excellent 60-GHz interconnect and antenna performance. The measured return loss and gain of each antenna from 56 to 66 GHz are and , respectively. Finally, the packaged transmitter and receiver chipsets, each working with a heat sink, have demonstrated beam-steered, non-line-of-sight links with data rates up to 5.3 Gb/s using 16-quadrature amplitude modulation single-carrier and orthogonal frequency division multiplexing schemes.