Electronics and Telecommunications Research Institute

Jin Bong Sung

Sung Weon Kang

Yun Tae Kim

Jung Hwan Hwang

Chang Hee Hyoung

Provided is communication apparatus and method using a transmission medium, in an environment where at least one transmitter and at least one receiver are connected to at least one human body which is a conductive transmission medium, in which the receiver requiring any information data requests a transmission to the transmitter or the transmitter sends a signal indicative of a transmission of required information data, and then, the transmitter provides the required information data to the receiver requiring the corresponding information data, thereby providing a communication environment without interference between the transmission means and the receiving means.

Communication apparatus using a transmission medium and method for the same

Provided is a dual antenna diversity transmitter and system having improved power amplifier efficiency, and further comprising switches in the dual antenna diversity transmitter and system, to minimize a DC input power consumed by the power amplifier depending on the required transmitting output power and operate efficiently the power amplifier, whereby signal linearity can be maintained and the power amplifier can be efficiently operated in a more simplified manner, as compared to the conventional high efficiency power amplifier.

Dual antenna diversity transmitter and system with improved power amplifier efficiency

The present invention relates to a variable gain amplifier for a high frequency band, and comprises a divider for dividing a input signal; a fixed variable gain amplifier for amplifying an output signal of the divider; a microstrip ring hybrid for outputting a plurality of signals which have the same or different phases, wherein the microstrip ring hybrid comprises a plurality of input terminals and output terminals having a constant impedance; a switch for selectively inputting an output of the variable gain amplifier to any one of the input terminals of the microstrip ring hybrid; a transmission line for delaying the output signal of the divider; and a combiner for combining each of the output signals of the microstrip ring hybrid and a signal passing through the transmission line and outputting the combined signal, wherein the output power is controlled by selectively inputting the output of the variable gain amplifier to any one of the input terminals of the microstrip ring hybrid by means of the switches, so that its input-output matching may be obtained irrespective of its gain.

Growing community of inventors

Seocheon, South Korea

Jin Bong Sung