5G mmWave Antenna: Qualcomm Antenna for Mobile Phones

This application note covers 5G mmWave antenna basics, including mmWave antenna requirements and the features of the Qualcomm QTM052 mmWave antenna used for 5G mobile phones or smartphones.

Introduction

The millimeter wave (mmWave) band uses frequencies from 30 GHz to 300 GHz in the electromagnetic (EM) spectrum. 5G uses frequencies up to 100 GHz, meaning the 5G mmWave frequency bands lie from 30 GHz to 100 GHz.

There are two frequency bands, FR1 and FR2, in 5G NR (New Radio). FR1 supports frequencies from 450 MHz to 6000 MHz, whereas FR2 supports frequencies from 24250 MHz to 52600 MHz.

We’re already familiar with MIMO, which stands for multiple-input multiple-output. This is used for a smaller number of transmit and receive antennas. Massive MIMO (M-MIMO) is a newer concept that utilizes a large number of antenna arrays, mainly 8x8, 16x16, etc. In Massive MIMO, a large number of antennas (usually 32 to 64) are used at the base station simultaneously to serve tens of users or mobile subscribers (MSs) in the same time-frequency grid. M-MIMO has many benefits over traditional MIMO systems.

mmWave Antenna Requirements

Figure 1 depicts massive MIMO antenna configurations. The following are the major driving factors for the widespread use of such antennas in the latest wireless technologies:

• Explosive data demand with limited spectrum
• More spectrum is available above 15 GHz in millimeter wave bands
• It is easy to scale up the use of active antenna elements in the available larger size antenna array.

Figure 1: Massive MIMO Antenna Array Configurations

Roger Corporation offers high-frequency PCB substrates for mmWave frequencies. For the 24 GHz range, they offer woven glass-reinforced, ceramic-filled, thermoset resins, etc., which are low loss, easily processed, and compatible with hybrid multilayers. For the 77 GHz range, they offer non-reinforced, ceramic-filled, PTFE resins, etc., which are low loss, isotropic, and provide the best electrical performance. The company also offers PTFE as well as thermoset resin-based antenna materials in various dielectric constants. PTFE offers low loss, whereas thermoset resin offers a rigid flat laminate and is easy for fabrication.

Qualcomm™ QTM052 mmWave Antenna

Figure 2: Qualcomm mmWave Antenna

Figure 2 depicts the QTM052 mmWave antenna from Qualcomm. This mmWave antenna module can be easily interfaced with the Snapdragon X50 5G modem from Qualcomm. It supports mmWave frequency bands viz. 26.5-29.5 GHz (n257), 27.5-28.35 GHz (n261), and 37-40 GHz (n260) with an 800 MHz operating bandwidth. These bands are mainly used in the US.

Advantages:

• The smaller size of these mmWave antenna modules, similar to a fingernail.
• Fiber optic-like fast speeds.
• Helps in achieving advanced beamforming, beam steering, and beam tracking. These features help in improving the coverage range and reliability of millimeter wave signals.

Disadvantages:

• Shorter range.
• Blockage due to walls and user hand.
• It doesn’t support the n258 (24.25 to 27.5 GHz) band.