Antennas are everywhere but when they are broughttogether they prove to be unruly neighbours. And with the available real estate in devices shrinking with each product launch, that heated contest for physical space will only increase. Such is the problem that has challenged designers for years, but now Birmingham-based Novocomms has found a solution.
Any device designer will tell you that there are fundamental constraints on antenna size and placement. Antennas emit energy in the form of electromagnetic waves.
With one antenna, all is fine; however, the moment you lay down an antenna next to another, trouble starts in the form of mutual interference. One antenna can be swamped by the strong signal that comes from the next, making its receiver deaf to the weaker signal it should be processing.
Two antennas are bad enough, but when devices are enabled with Wi-Fi, Bluetooth and GPS, and when up to four 4G MIMO antennas are required for cellular communications, things become crowded. And that’s before the arrival of 5G into the neighbourhood.
Yet no longer. At Novocomms, engineers started with the assumption that designers building devices would want their antennas operating at the same time. And why not? It’s not unusual for a mobile device to be running apps that rely on GPS and Bluetooth while, say, streaming a video over Wi-Fi or the cellular network.
The only sensible solution is a new approach to antenna design. So the engineers at Novocomms design a suite of antennas together as a single system and then install that system into the device as a single cohesive unit. Chief Executive Officer Dr Sampson Hu explains how Novocomms takes this different approach.
Dr Hu says: ‘We accept that the antennas will be crowded together and that they will emit radio-frequency signals that can interfere with one another.”
To reduce interference, the company uses many standard techniques such as polarisation.
He continues: “We also make the antennas directional and point them away from one another. We do this by modifying the physical shape of the antenna in three dimensions.
“We also try to make it easier for antennas to ignore extraneous signals, using filters in a non-traditional way.”
Filters have to be considered, he says. “Normally, the filters used in antennas are bandpass filters. That is, they allow through only signals in the desired frequency band. The problem with digital bandpass filters is that they don’t get applied until after the analogue signal reaches the receiver and is converted to a digital stream.”
Dr Hu adds: “We know the frequencies at which the surrounding antennas are transmitting, so our analogue filters look for those specific frequencies and, in effect, short those signals to ground, dissipating their energy while passing the desired signals undisturbed to the receiver.
“With all this technology in use, we can place antennas physically close together.”
Dr Hu says one of the advantages Novocomms clients appreciate is the firm’s nimble approach.
“Along with a tight-knit group of engineers, most of whom have been awarded their PhDs in antenna design, we have a well-established supply chain that works with major manufacturers of smart watches and laptops, and we are experienced in quickly solving problems.”
To stay ahead of the competition, Dr Hu says, the company has had to invest heavily in research.
One of Novocomms’ patented designs dynamically retunes the low-band response while maintaining the stability of mid-high bands. These tuneable solutions can fully support 5G sub-6GHz frequency bands to meet a customer’s most challenging requirement within the limited antenna dimension.
“I am particularly proud that our engineers have designed the world’s smallest 5G WWAN antenna-tuneable solution for a major multinational,” he says.
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