Seeking to simplify the design of converged mobile devices, Ethertronics has expanded its Savvi series of wideband and multi-band ceramic antennas with units that support Bluetooth, GPS, WLANs, and WiMAX, as well as a dual-band PCS/WiMAX antenna. These units leverage the company’s isolated magnetic dipole (IMD) technology, which provides high frequency stability and reduced inter-element crosstalk derived from exceptionally high RF isolation.

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Therefore, every antenna in the Savvi line has the ability to co-locate with the main antenna of a wireless device without experiencing frequency shift or RF interference, which can ultimately hinder performance and reception. According to Rick Segil, vice president of Ethertronics, the high isolation can also be used to implement Rx diversity in the main RF front end, which can address the rising demand for more bandwidth and greater signal integrity in wireless handsets.

Segil also states that another critical benefit of these devices enabled by IMD technology is high efficiency. Efficiency not only contributes to improved Rx sensitivity and Tx range, but can also contribute to extended battery life, and generally ranges above 60% for all the devices. According to Segil, achieving this high efficiency was a challenge due to the small form factors and high bandwidths of the antennas based on the technology.

For example, the smallest of these recent additions, the Bluetooth antenna, measures 5 mm x 3 mm x 1.3 mm. Similarly, the WLAN ceramic antenna measures 7 mm x 4 mm x 1.3 mm, and operates at 2.4 GHz to 2.5 GHz, and 4.9 GHz to 5.8 GHz. While the larger (14 mm x 4 mm x 1.3 mm) the WiMAX antenna operates on either the 2.3 GHz, 2.5 GHz or 3.5 GHz bands. The PCS/WiMAX unit is 9.6 mm x 3 mm x 1.3 mm, and covers 1.93 GHz to 1.99 GHz, and 2.5 GHz to 2.7 GHz.

Segil states the basic design strategy was to settle on a single ceramic substrate material with good inherent RF-isolation characteristics, and then to concentrate on the geometric design of the IMD for the desired bandwidth. The use of IMD topology provides superior isolation compared to both the conventional-monopole- and planar-inverted-F-antenna (PIFA) topologies.