ISM.10 ISM Device Passive Mode Antenna Testing

What is the problem or concern we are addressing?

Post-integration optimization of antenna performance through physical and electrical matching as well as orientation and position changes. All antennas are sensitive to their surrounding environment. Once an antenna is integrated into a product it is very common for the exact tuning of the antenna to differ from the design target or development board implementation. The resonant frequencies for most antennas can be adjusted either by implementing a lumped element electrical matching network, or through small physical modifications to the antenna itself. This tuning effort results in optimal performance of the product as a whole.

NOTE: This testing includes the performance of the GPS antenna and the receiver together. Antenna performance metrics such as efficiency, gain and axial ratio are not provided by this testing. Taoglas offers a separate service for measuring these antenna performance metrics.

The Process

  • Taoglas will modify your prototype device to allow for direct access to the antenna feed point at the beginning of your feed transmission line.
  • The antenna will be matched to the desired operating frequencies of the product with all mechanical system elements in place including the enclosure, any batteries, displays or other system elements. The tuning is intended to account for everything in the system in the typical use-case so this includes any human body interaction that would be encountered in certification. If the device is worn or held by a person a human body phantom part will be used to account for this.
  • Measure the radiation pattern and efficiency of the antenna with it installed in the device or on the board as close as possible to the real use case configuration.
  • A complete report detailing test set up, results and conclusion.
What does Taoglas need?
  • We will need 2 copies of your device including all the bits and pieces. The units do not need to be fully functional (i.e. firmware/ software need not be complete), but they need to be built up representative mechanical samples.
  • Things like any battery, LCD display, peripherals, cables, etc. all mounted in some sort of enclosure that’s at least close to what the final enclosure will be like. SLA or FDM proto enclosures are sufficient but the final plastic material can yield slight differences in performance.
  • 3D PDF or eDrawing files for your mechanical assembly. We really do need the ability to hide parts, do cross-sections and make measurements so an eDrawing with these features turned on is highly recommended.
  • We need the schematic for all the boards in the device. PDF format at a minimum and native Altium files if you happen to use Altium.
  • PDFs of your PCB layout for each board, all layers. Again if you use Altium, then native Altium files would also be helpful. Please include a document defining the PCB stackup, layer thicknesses, materials and finishes for the PCB.
  • A spreadsheet of your bill of material for each PCB in the design.

Taoglas will compile a report on the antenna measurements including:

  • Details of any electrical or mechanical tuning techniques.
  • Matching network diagram and values include device samples with implemented changes.
  • Return loss plots of before and after.
  • Radiation pattern plots for each band.
  • Efficiency plots vs. frequency for each band.