World's smallest claim for UMTS duplexer

Epcos has developed the world's smallest duplexer for use in UMTS mobile phones.

Epcos has developed the world's smallest duplexer for use in UMTS mobile phones.

Using SAW technology, the duplexer measures only 3.8 x 3.8 x 1.35mm.

Duplexers are key RF components within third generation UMTS and CDMA phones.

The devices are used to separate the signals sent and received simultaneously at different frequencies, thus permitting trouble free operation at the highest possible datarates.

At the moment conventional microwave ceramic duplexers have a form factor of 10 x 4.5 x 2mm.

The new SAW duplexer from Epcos reduces the required area by a factor of 3.1 and the volume by as much as 4.6.

These space savings are extremely important as this is the only way of implementing compact multiband/mulitmode phones that are capable of accessing today's mobile radio networks (EGSM, PCN) and the new UMTS services.

These new SAW components also offer considerable space savings over FBAR (film bulk acoustic resonator) technology.

At the heart of this new duplexer is a SAW chip that provides the filter functionality that is required in the 2.1GHz band.

To date, SAW duplexers were common only in the 800MHz AMPS band.

Due to sustained development of SAW technology, Epcos has been able to extend duplexer functionality to frequencies above 2GHz.

Due to the need for matching to the surrounding circuitry and for effective decoupling of the send and receive branches, duplexers not only require SAW filters but may have the need for another five passive components.

As well as the development of the new 2.1GHz SAW chip, Epcos reached another milestone in product development with the design of a mulitlayer LTCC (low temperature cofired ceramic) substrate.

This allows for the complete integration of these 'extra' components into one package, the substrate doubles as the carrier for the SAW chip in CSSP (chip-size SAW package) technology, patented by Epcos.

It is now possible to implement a complete duplexer scarcely larger than the actual SAW chip.

By combining the 2.1GHz SAW duplexer chip, CSSP technology and the enormous integration potential of the LTCC substrate, Epcos has managed to miniaturise the complete front end for third generation mobile phones.

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