July 21, 2008

Ultra-lightweight broadband WiMAX filters

Radio Frequency Systems has unveiled an entirely new family of dual ultra-lightweight RF filters designed for worldwide interoperability for microwave access (WiMAX) applications. Founded on the company’s patented polymer-based air-cavity filter technology, the filter family boasts a body-weight of just 300g (10 ounces)—less than 50 percent of that of competing WiMAX filter solutions.


The family comprises four separate filters with passbands designed to support the 2.2, 2.3, 2.5 and 3.5GHz WiMAX sub-bands-the widest range of sub-bands currently allocated for WiMAX applications across the Americas, Europe and the Asia-Pacific regions. Specifically designed for time-division domain (TDD) WiMAX applications, all member of the RFS WiMAX broadband filter family exhibit common package dimensions, regardless of the filter's passband frequency. This streamlines end-user logistics and simplifies filter mounting.

The common demand from OEMs in the WiMAX domain is for a broadband filter that can be built into active WiMAX equipment, such as Micro BTS or remote radio head. A filter family that fits into the same package dimensions, regardless of its WiMAX band, simplifies OEM logistics and equipment development. RFS achieves this, with its unique new range of WiMAX broadband filters-‘a one-size-fits-all' ultra-lightweight WiMAX broadband filter family.

RFS's unique polymer filter technology provides a filter with a body weight of less than half that of equivalent legacy aluminum filters, yet retains optimal filter performance. Mechanical stability and high-precision mechanical tolerances are ensured by incorporating glass fiber and mineral filler reinforcement in the polymer material. Optimum thermal expansion properties are achieved via a unique blend of polymer materials.

Founded on high-Q cavities and engineered to provide premium RF performance, the new WiMAX filters boast low insertion loss (typically 0.3dB in-band at room temperature) and excellent power-handling capabilities.

Each member of the WiMAX filter family provides two filters within its silver-plated combline-construction filter body. The two-channel filters feature multiple resonators-two x six resonators within the 2.2GHz and 2.3GHz variants; and two x eight resonators in the 2.5GHz and 3.5GHz models-with all resonators located in exactly the same position for easy interchangeability. All this is offered in a compact slim-line (40mm-thick/1.5-inch-thick) package of less than 0.7 liters (40 cubic inches).


Features and Advantages
Suite of four filters supporting sub-bands in the WiMAX 2.2 to 3.5GHz range Cover the widest range of sub-bands allocated for WiMAX
High-Q cavity technology providing low insertion loss Results in premium RF performance and excellent power handling
Common filter package dimensions Streamlines equipment development
Body weight of just 30g (10 ounces) Weighs less than 50% of competing aluminum filters, for streamlined site logistics, installation and wiring
Glass-fiber construction with mineral-filler reinforcement of unique polymer technology Precise tolerances and mechanical stability with optimal thermal expansion properties
Each filter incorporates multiple resonators in identical positions in filter body Provides easy interchangeability of resonators