The next generation of cellular technology is going to impose some exacting requirements on the antenna subsystems of smartphones

By Brian Santo, contributing writer

Skyworks
Solutions has added an antenna tuning switch to its Sky5 product line of
modules for 5G New Radio (NR) products. The tuner is designed for use in 5G handsets,
operating from 600 MHz to 6 GHz for LTE Advanced Pro to 5G standards.

There are a
number of design challenges facing manufacturers of 5G handsets, not the least
of which is the increase in the number of antennas that each handset is likely
to integrate. Handsets for previous generations of cellular networking had a
maximum of four, though they frequently incorporated fewer.

A new technology
introduced in 5G handsets is multiple-in, multiple-out (MIMO) technology. It
appears that 5G handsets (due to begin hitting the market in early 2019) will
start with 4 × 4 MIMO, meaning a minimum of four antennas. Some of the first
handsets might have as many as seven, said Skyworks.

Antenna tuning
plays a critical role in maintaining smartphone power efficiency and battery
life, said the company. Meanwhile, the migration to full-screen infinity displays
and expanded functionality limit the amount of board space available. That
means that tuning switches need to be efficient and small.

The frequency
range of the new SKY5−9256-701LF
advanced aperture tuner is 600 MHz to 5.9 GHz. Skyworks describes the tuner as
having reliable linear operation and extremely low on-resistance (Ron
of 1.1 Ω) and off-capacitance (Coff of 145 fF). Skyworks said that
this allows system designers to recover the 1.5-dB to 3-dB gain degradation caused
by shrinking antenna sizes.

A functional diagram of the SKY5−9256-701LF advanced aperture tuner. Image source: Skyworks.

In the datasheet,
the company said that no external DC blocking capacitors are required as long
as no DC voltage is applied on any RF path.

As for size, the
device is mounted in a QFN 10L package, measuring roughly 1.5 × 1.1 × 0.45 mm.

The company also
introduced four other antenna tuners not specifically aimed at 5G applications.
One matches the same frequency range as the SKY5−9256-701LF (600 MHz to 6 GHz), while the others
cover narrower slices of spectrum below 6 GHz. The list of the company’s
antenna tuners is here.

The Sky5 portfolio
for 5G NR applications also includes a power amplifier module (SKY5-8250) with
integrated filtering and dual-path low-noise amplifiers (LNAs) supporting n77/n78/n79
and B42/B43/B48 bands and a diversity receive module with integrated filtering
and dual-path LNAs (SKY5-3728). It supports the same bands as the power amp
module.

The other two
parts in the family are a cellular vehicle-to-everything (C-V2X) front-end
module with Class 2 power and integrated gain control (SKY5-5761) and an LAA
receive module with integrated bypass LNA and variable gain control (SKY5-5811).

Skyworks
said that the parts are in production and available for sampling. The company did
not respond to requests for pricing information.