QUESTION

Question

Hello,

We have a requirement for an antenna that would operate within a bandwidth of 865-867 MHz, to support our metering application. We are about to layout our board but antenna selection is something we would like to pay more attention to before we actually get started with the layout design.

The target dimension of our PCB is 50x30 mm that integrates to smart meter and serves as communication module to it.  As you may have already figured that PCB is small form factor and hence antenna efficiency becomes more critical here. So, I kindly request you to help us with the range of antennas that are applicable to said bandwidth. We would like to share our design files with you too, so we can have a quick simulation run, to find out efficiency in ideal scenario.

Kind Regards,

Nayab Kidwai

Answer 1

Hello Nayab,

As you mentioned, yes board length is going to be an issue at this frequency. It will have a direct impact on the efficiency. Sometimes the addition of things such as the power supply harness will help to add length to the product allowing the antenna to see more ground reference for the antenna, so keep this in mind in your design.

Another critical design guideline to keep in mind is metal objects near the antenna. Things such as batteries mounting right next to the antenna or tall components like connectors will degrade bandwidth or shift the resonant frequency of the antenna causing degraded performance.

Most antenna are tuned to their environment hence the recommendation of lumped element matching components. Off the shelf antennas are designed in free space so when they are integrated into a device housing there usually is a need to shift the frequency a little bit using on board 0402 inductors and capacitors. Antenova offers services to aid in designing in antennas from start to finish.

We have several surface mount antennas that operate in that frequency range, however, they will take up at least a quarter of the board space. For surface mount antennas I would suggest looking at Kirbii, Latona or Grandis.

We also have flexible printed circuit antennas like the Montana and Inca that can be mounted to the inside of your chassis if that is an option.

I will pass on your contact information to our local sales rep. to contact you for further discussions.