800 MHz Rebanding Duplexer

K&L Microwave Launches New Custom ESMR Solution
For FCC Reconfiguration of 800-MHz Bandwidth

Salisbury, MD (April 13, 2006)—K&L Microwave, Inc., part of Dover Corporation’s Microwave Products Group, has released its new WSD-00420 800-MHz re-banding duplexer in response to the recent Federal Communications Commission (FCC) mandate for signal spectrum separation of incompatible wireless technologies.

The new duplexer, for use in Enhanced Specialized Mobile Radio (ESMR) systems, protects emergency services communications from interference from ESMR signals. Emergency services providers include police, firefighters, and medical technicians.

“Commercial wireless systems have propagated wildly in the recent past,” says Rafi Hershtig, Vice President of Advanced Engineering and R&D for K&L Microwave. “Many of these devices operate on the 800-MHz band, which is the same band that public safety providers use. Here, the close proximity of numerous antennas coupled with ‘line-of-sight’ scenarios can potentially saturate the noise floor level of the transceivers, consequently escalating the problem of dropped calls.”

Thus, to avoid potentially life-threatening situations, the FCC has mandated the reconfiguration of the 800-MHz band so that ESMR operators can communicate without interference among the higher segments of this bandwidth.

In response, K&L has designed and released the WSD-00420 ESMR duplexer module, which operates between 817-824 MHz within its receive filter, while its transmit filter operates between 862-869 MHz. The new offering’s downlink transmit filter enables a sharp roll-off into the guard and expansion bands below 862 MHz, thus mitigating the ESMR downlink out-of-band emission.

Based on K&L’s U.S. patents US6236292 and US5936490, the WSD-00420’s asymmetric design facilitates placement of finite transmission zeros below a pass-band, utilizing a cascade of Tri-Sections in TE01d single-mode ceramic resonators. This configuration offers high-Q, temperature stability, and excellent power-handling capabilities (100W CW). The WSD-00420 maintains spurious-free response up to 2700 MHz. Units can be installed standalone, or three across in a 19" rack.


“The development of this 800-MHz duplexer is just one example of K&L’s dedication to the markets it serves,” Hershtig asserts. “K&L recognized a crucial need, and responded quickly by creating an ideal customized solution.

“K&L’s ability to provide custom solutions is the result of many years of mastering, applying, and integrating new technologies,” concludes Hershtig. “It is through this expertise that K&L stands as the leader in the microwave and RF filter industry, offering broad capabilities in in-house design and manufacture while ensuring exceptional customer support and on-time delivery.”

About K&L Microwave

K&L Microwave is a subsidiary of Dover Corporation, and is recognized by top-tier defense contractors and wireless infrastructure providers as a world leader in the design and manufacture of RF and microwave filters, duplexers, and integrated assemblies. With offices in the United States, China, the Dominican Republic, and the United Kingdom, Salisbury, Md.-based K&L is ISO 9001:2000- and ISO 14001-certified, and offers customers the most extensive range of filter-based products in the industry, spanning from 0.3 MHz to 94 GHz.

For more information, visit K&L Microwave’s Web site at http://www.klmicrowave.com/.

K&L Microwave
Jeff Burkett
Director of Sales and Marketing
Tel: +1 410-749-2424
E-mail: jburkett@klmicrowave.com