Lucent Technologies Inc.

Agere Systems Guardian Corp.

Mark Francisco

Ross Gilson

Benny Pruden

Ralph Francis Trambarulo

Christopher Albano

Myung-Kul Kim

The specification relates to a radio frequency (RF) multiport, multiband semiconductor and transmission circuit. Each port in the multiport circuit is linked to a second port utilizing a semiconductor switching leg. A semiconductor switching leg is biased to either transport thereover an RF signal or to prevent its transport. In an embodiment of the present invention utilizing diodes as an active device within each semiconductor switching leg, a DC biasing signal is applied through an inlet and outlet inductor, thus allowing DC current to pass through the diode for biasing, but preventing RF signal loss to ground. Capacitors are used for RF signal coupling and DC blocking. One embodiment of the present invention is utilized with a dual band cellular/PCS device, with either band selectable for transmission and reception over either an internal antenna or, in the alternative, an external antenna port. Transmission from the multiport, multiband semiconductor switch to one or both antenna ports is accomplished utilizing stripline with via arrays incorporated within the multi-layer printed circuit board.

Multiport, multiband semiconductor switching and transmission circuit

In a communications system, a multi-band power amplifier is employed to increase the power level of a signal for transmission over one of multiple frequency bands. In addition, a multi-band low noise amplifier is employed to scale the signal level of a signal received from one of the multiple frequency bands. In accordance with the invention, each multi-band amplifier is designed such that the gain values afforded by the amplifier to the components of the communication signal within the multiple frequency bands are significantly higher than the gain values to the signal components outside those bands.

Communications system using multi-band amplifiers

In a communications system, a power amplifier is dynamically biased in response to a control signal indicative of the required transmission power. In delivering relatively high transmission power, the DC operating point of an amplifying element in the power amplifier is placed far from the cutoff and saturation regions of the output characteristics of the amplifying element. As a result, the corresponding input signal at a high drive level to the power amplifier is virtually undistorted thereby and, at the same time, a high power efficiency is achieved. In delivering relatively low transmission power, although the DC operating point is placed relatively close to the cutoff region of the output characteristics of the amplifying element, because of the corresponding input signal which is at a low drive level, the power amplifier minimally distorts the input signal. However, a high power efficiency is maintained because the input DC power to the power amplifier is reduced as well as the transmission power.

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Millstone Township, NJ, United States of America

Mark Francisco