Wireless Technologies
Figure 3: Wireless protocols are typically differentiated by
range, data rate and applications, even those that operate at
the same frequency
very low data rates but over long distances and at relatively low
power levels, while higher data rates are typically restricted to
shorter distances but may still require more system power to
function.
Operating frequency is also defined by the protocol and most
engineers will be at least somewhat familiar with the licensefree
bands allocated for Industrial, Scientific and Medical (ISM)
applications and, within these, the 2.4GHz band used by many
of the most popular protocols. Despite using the same part of
the spectrum, these protocols offer various ranges and data
rates, which influences both their relative power requirements
and the overall cost of radio devices. It is important to realise
that the RF electronic circuitry defines the protocol, whereas the
antenna simply receives and transmits RF signals fed to it by
the electronics, irrespective of the protocol used.
This means that while the RF SoC/SiP used may differ between
protocols, it is actually possible to use the same antenna
design for any protocols that operate at the antenna’s intended
frequency, such as those operating at 2.4GHz (WiFi, Bluetooth,
Zigbee, etc.). This means, of course, that one antenna can
support several protocols. Having said that, there remain other
relevant considerations when selecting an antenna, such as
the physical space available and its location within the product.
This will define the shape of the antenna, which may need
to conform to a given profile in order to support the required
frequency or bandwidth.
Figure 5: Design options include PCB-mounted and
remotely located. Often, the application will dictate the most
appropriate approach
Antenna design expertise
Molex has been designing, manufacturing and supplying
standard and custom integrated antennas for two decades, for
mobile and IoT applications in various volumes and for leading
device manufacturers around the world.
The Molex antenna product portfolio covers all the major
protocols used today, as well as proprietary solutions, with a
focus on embedded (PCB mounted) and internal cabled antennas,
when performance requirements may dictate their use.
Embedded antennas can be extremely small and manufactured
from ceramic and plastic, as well as stamped metal,
weighing just a few grams (Figure 4). Cabled antennas can
be made using PCBs, both rigid (FR4) and flexible, as well
as stamped metal. These capabilities make it simple to find
the most appropriate antenna design, whatever the application.
Even though they can be made very small and compact,
embedded antennas still come with design requirements that,
if followed, will help ensure that the antenna performs as the
specification demands. Many factors, such as the size of the
PCB, its shape and where the antenna is mounted on the PCB
can all impact how the antenna performs.
To support the product portfolio, Molex has produced a
library of application specifications. These are engineering
documents that go beyond the standard antenna data sheet.
They include not only performance information but a reference
design, with advice on where and how to locate the antenna on
a PCB. Perhaps most importantly, the application specification
provides an estimate of the antenna’s operation and how this
will vary based on its location on a PCB, taking into account its
proximity to other components and features such as batteries,
metal shields and the cable itself for cabled antennas. These
application specification documents provide essential guidelines
that system designers should read to understand how to
best engineer the antenna into each system.
In most cases, the information provided in the application
Figure 4: Antennas can be designed and manufactured to
meet the most demanding space constraints
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