Case Studies

Ceramic components help antenna manufacturer reduce radiation levels (Sarantel 28/09/04)

Miniature antenna manufacturer Sarantel remains one of only a handful of companies that has been able to significantly reduce the near field of the antenna, which in turn reduces the specific absorption rate (SAR).

The patented PowerHelix design is made up of copper tracks deposited onto a small ceramic cylinder and then individually and automatically laser trimmed for optimum frequency response. 

As part of the extensive research that was undertaken to develop the technology, Sarantel worked with Morgan Technical Ceramics, a leading expert in the design and manufacture of technical ceramics, to identify the most appropriate ceramic material for the antenna.

"We needed a ceramic manufacturer that could provide materials expertise, and consistently produce high quality ceramic components to tight tolerances in high volume," comments Greg Harding, Supply Chain Manager, Sarantel.

Morgan Technical Ceramics developed a ceramic that offers low energy loss to make it an excellent dielectric resonator for microwave applications. Ceramic is an attractive, low-cost alternative to metallic resonant cavities (used in conventional antennas) and has the advantage that it can be manufactured to a small size and still retains a high performance.

"We had very specific requirements to help enable the many technical benefits of our antenna design which make it ideally suited for mobile, automotive and other applications," explains Harding.

The high dielectric ceramic and twisted loop design used in Sarantel's PowerHelix technology constrains the near field of the antenna and as a result, the antenna offers significant performance, cost and technical benefits including omni-directional operation, an integrated ground plane and no detuning effect from the user.

The other key specification set by Sarantel was that the ceramic components were required in consistent-quality, and high-volume to enable the company to meet rapidly increasing demand. Morgan Technical Ceramics refined its production techniques to meet Sarantel's requirements, and ensure guaranteed process stability and consistent end product in the volumes they required. 

Morgan Technical Ceramics manufactures a wide range of dielectric and coaxial resonators to meet the demands of microwave applications for high performance, low cost devices in small, medium and large quantities. Each ceramic is made of different composition to give specific dielectric properties, and in changing the size of the components different frequency bandwidths can be achieved. The company offers the following dielectric options - D20, D30, D34, D43, D77, D88, which are ideally suited for a range of other applications, including frequency filters used in wireless cellular / radio systems, dielectric resonator oscillators and microwave radar systems.