Millimeter Wave Specific Challenges mmWave Design Challenges Informational

How do I design a millimeter wave antenna in package for a consumer wireless device?

Antenna-in-Package (AiP) is the dominant architecture for mmWave consumer wireless devices (5G smartphones, laptops, VR headsets) because it integrates the antenna array directly into the IC package, eliminating the board-level antenna and the lossy package-to-board-to-antenna transitions. Design approach: (1) Architecture: the mmWave transceiver RFIC (containing the PA, LNA, phase shifters, and beamforming network) is mounted on a multilayer organic or glass substrate. The antenna elements (typically patch antennas or slot-coupled patches) are formed on the top layers of the same substrate. The feed network connects the RFIC output to the antenna elements through the substrate vias and traces. The entire module (RFIC + substrate + antennas) is encapsulated in mold compound and mounted on the phone PCB. (2) Antenna elements: patch antennas are the most common choice for AiP: planar (compatible with multilayer substrate fabrication), well-characterized radiation pattern (broadside, pencil beam), reasonable bandwidth (5-10% for a single-layer patch, 15-25% for stacked or aperture-coupled patches). At 28 GHz: each patch is approximately 3 × 3 mm (lambda/2 × lambda/2). At 39 GHz: approximately 2 × 2 mm. (3) Array size: consumer 5G devices use 4-16 element arrays per module. A 4-element linear array (1×4): provides beam scanning in one axis (typically elevation). An 8-element planar array (2×4): provides scanning in both axes with approximately 12 dBi gain. Larger arrays (16 or 32 elements): higher gain but larger module size. (4) Substrate: organic (build-up layers on a BT or ABF core): lowest cost, widest availability. Dk = 3.0-3.5. Loss tangent = 0.003-0.008 at 28 GHz. Suitable for 28-39 GHz. Glass (TGV technology): ultra-flat surface (< 0.5 um roughness), tight Dk tolerance (±1%), and excellent dimensional stability. Dk = 4-6 (borosilicate) or 3.3 (fused silica). Emerging technology for high-performance AiP. LTCC: excellent RF properties but higher cost than organic. Used in some automotive radar AiP.
Category: Millimeter Wave Specific Challenges
Updated: April 2026
Product Tie-In: mmWave Components, Substrates, Packaging

mmWave AiP Design

The AiP approach has transformed mmWave consumer device design by moving the antenna from the device PCB into the module, where it can be precisely controlled and tested as a complete unit.

Common Questions

Frequently Asked Questions

How many AiP modules does a 5G phone need?

Typically 2-3 modules per phone. The multiple modules provide: spatial diversity (different orientations for different hand positions), NLOS coverage (if one module is blocked by the hand or head, another module on a different phone edge can maintain the link), and hemisphere coverage (modules on top, left, and right edges collectively cover most of the upper hemisphere). Example: Qualcomm QTM525 module: 4-element array, one module per phone edge. Samsung Galaxy S21: 3 modules. Apple iPhone 12 (mmWave model): 4 modules (2 on the sides, 2 on the top/bottom). Each module operates independently with its own RFIC and antenna array. The baseband selects the best module in real time (beam switching latency < 1 ms).

What is the typical AiP module size?

Current generation (2022-2025): 10 × 10 × 1.5 mm for a 4-element array at 28 GHz. 8 × 8 × 1.2 mm for a 4-element at 39 GHz (smaller wavelength = smaller patches). Weight: 0.3-0.5 g per module. Future: modules are shrinking as RFIC technology advances (smaller RFIC die, more integration). Target: 7 × 7 mm for 8-element arrays by 2026. The module thickness is constrained by: the substrate layer count (4-8 layers × 0.05-0.1 mm per layer), the RFIC die thickness (0.1-0.2 mm), and the mold compound overmold (0.2-0.5 mm). Total: 1.0-1.5 mm is typical.

What performance can I expect from an AiP module?

Representative specifications for a 5G UE AiP at 28 GHz (4 elements): EIRP: +20 to +25 dBm (TX, per module). Scan range: ±60°. Gain at broadside: 10-12 dBi. G/T (receive figure of merit): -10 to -6 dB/K. EVM: < -25 dB for 64-QAM. Noise figure (receive): 5-7 dB (including all losses from antenna to baseband). These specifications enable data rates of 1-4 Gbps per user at distances of 100-200 m from the base station (line-of-sight). In NLOS (non-line-of-sight) conditions: the range drops to 50-100 m, and the data rate drops to 500 Mbps - 2 Gbps (depending on the reflection/diffraction environment).

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