Integrating an antenna is a crucial step in a wireless product design. Antennas behave differently to other digital integrated circuits (ICs). This creates a unique set of design challenges and considerations that traditional design cycles do not account for.
With devices getting smaller, designs are becoming intrinsically less RF friendly. Circuit boards are shrinking, yet are tightly packed with noisy components. An antenna cannot be simply ‘added’ at the end; RF must be a priority from the outset.
More product designers are facing this challenge. To design great wireless products, designers need to change their approach. Our proven cycle considers wireless design first, and it’s suitable for projects of all scopes and sizes. Here’s how we recommend that you approach your wireless product design.
- Research
- Architecture Layout
- Board Design
- Gerber Review
- Design Test
- Pre-production
- Mass production
This video, an extract from a webinar hosted by Antenova's Antenna Application Specialist Geoff Schulteis, introduces the wireless design cycle and discusses the research stage - including some of the pros and cons of a range of different antenna types.
Research
The wireless design cycle starts at the same time a design project does. Wireless technologies are the enablers of connectivity and there’s lots of them. Likewise, antennas are also available in a variety of forms. Designers that are aware of the variety of options available will be more empowered to fulfil a brief.
Wireless technologies
There are wireless technologies available to suit any sort of device. Whether you require long-range connectivity without large power requirements, or precision tracking, there is a technology to suit. While selecting a technology, there are a number of factors to consider:
- Data throughput. How talkative will your device be? Will it require tens of megabytes or just a few bytes?
- Range. How far away will the device be from the base station?
- Power consumption. How much life should your battery provide?
- Certifications. To launch a device on a cellular network, you need to pass all the relevant certifications. In North America, the performance of an antenna will be intensely scrutinised. The region has some of the toughest passing criteria for certification in the world.
There is no one-size-fits-all wireless technology. The right choice will depend on data throughput requirements, range, power consumption and certification needs. More designs are incorporating multiple wireless technologies, too, making the choice of complementary antennas crucial.
| Cellular | GNSS |
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| WLAN | LPWAN/ISM |
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The different wireless technologies available.
Antennas
It’s the antenna that makes it wireless. Antennas are therefore crucial components in the Internet of Things. The diversity within IoT reflects the availability of antennas; antennas in a huge variety of configurations are capable of connecting devices.
Surface-mounted antennas
Surface-mount device (SMD), sometimes known as surface mount technology (SMT), antennas are far and away the most popular type of antenna available today. These mount directly to the PCB, and come in a variety of shapes, sizes and materials. These are commonly available in highgrade dielectric laminate substrates, ceramic, or even stamp metal. There are some advantages that come with their use:
- SMD antennas are tiny. Some antennas measure just a few millimetres.
- They’re low cost and easy to assemble using pick and place equipment.
- Within a compact form, they offer high levels of performance.
As SMD antennas are inexpensive, yet offer great performance within a compact form, their popularity is understandable. However, to enable a surface-mounted antenna to perform well, the design must be optimised.
RF Modules
Like an SMD antenna, modules can be placed directly on the PCB. The advantage these have over standard surfacemounted antennas is that they come pre assembled. The antenna will already have a chip and other key components.
These work excellently for GNSS applications. They effectively offer a ‘dropin’ solution, which means that designers do not need to spend time designing in complex RF circuitry.
Case-mounted antennas
For applications that require tiny circuit boards, surfacemounted solutions are not always the most appropriate solution.
And, for applications that use non-RF friendly materials – like metal – it will always prove difficult to achieve strong wireless performance levels with an embedded antenna.
Antenova’s patented REFLECTOR technology isolates case-mounted antennas from noise. By using a ferritelike layer the antenna can perform with minimal losses, even when mounted on metal.
With just a single connection to the circuit board, these antennas do not require ground plane space on the circuit board. This frees up space for other components. It also means the designer is more free to place switches and other noisy components where is most convenient.
Flexible printed circuit board (FPC) antennas
As space-saving antennas go, FPC antennas are probably the best. These antennas have an extremely low profile yet offer unparalleled design flexibility.
FPC antennas are commonly deployed within wearables and small handheld devices. They can wrap around the housing of a device, all while connecting to the circuit board via a single UFL connection.
Antenova’s flexiiANT antennas are available in a variety of connection-types and cable lengths to enable their use within ultra-compact devices.
