SPE-11-8-051/E

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1. Introduction

The FXP810 has a peak gain of 1.5dBi at 2.4GHz and efficiencies of 60-70%, increasing

to 5dBi and 80-90% along bands 4.9GHz to 6GHz.

At 31*31*0.1mm in size this antenna is uniquely valuable for small tag type mobile

devices in that it can slip between the battery and the main PCB ground of

small devices to get increased performance from the ground coupling effect. Only the

top 6.5mm radiating element needs to protrude out from the side of the main board,

allowing such devices to have the highest possible performance at smallest possible

dimensions, it accomplishes this because it does not need clearance or footprint space

on the device board itself that all on-board chip, loop and patch antennas need.

Many module manufacturers specify peak gain limits for any antennas that are to be

connected to that module. Those peak gain limits are based on free-space conditions.

In practice, the peak gain of an antenna tested in free-space can degrade by at least

1 or 2dBi when put inside a device. So ideally you should go for a slightly higher peak

gain antenna than mentioned on the module specification to compensate for this effect,

giving you better performance.

Upon testing of any of our antennas with your device and a selection of appropriate

layout, integration technique, or cable, Taoglas can make sure any of our antennas’

peak gain will be below the peak gain limits. Taoglas can then issue a specification

and/or report for the selected antenna in your device that will clearly show it

complying with the peak gain limits, so you can be assured you are meeting regulatory

requirements for that module.

For example, a module manufacturer may state that the antenna must have less than

2dBi peak gain, but you don’t need to select an embedded antenna that has a peak

gain of less than 2dBi in free-space. This will give you a less optimized solution. It is

better to go for a slightly higher free-space peak gain of 3dBi or more if available. Once

that antenna gets integrated into your device, performance will degrade below this

2dBi peak gain due to the effects of GND plane, surrounding components, and device