Abstract: A programmable surface acoustic wave filter and methods thereof including a piezoelectric substrate, a ground electrode formed in a comb structure on the piezoelectric substrate, a plurality of output electrodes formed in comb structures on the piezoelectric substrate and alternately disposed together with the ground electrode, and a switching unit performing a switching operation so as to selectively transmit output signals output from the plurality of output electrodes to an output node. As a result, a filtering characteristic of the programmable surface acoustic wave filter can be programmed in a desired format.

Abstract: Provided are an antenna and a portable wireless apparatus including the antenna. The antenna includes a plurality of antenna elements each having different frequency properties, and a branching filter having a plurality of filters which are connected to the antenna elements, respectively, the filters having pass bands corresponding to frequency properties of the connected antenna elements, and restricting transmission/reception bands of the antenna element to the respective pass bands. Accordingly, since only a single antenna element having a resonant frequency corresponding to used frequency is selected by a filter and functions as an antenna independently, the antenna having a broad band, a small size and a simple structure, and the portable wireless apparatus including the same is provided.

Abstract: A programmable surface acoustic wave filter and methods thereof including a piezoelectric substrate, a ground electrode formed in a comb structure on the piezoelectric substrate, a plurality of output electrodes formed in comb structures on the piezoelectric substrate and alternately disposed together with the ground electrode, and a switching unit performing a switching operation so as to selectively transmit output signals output from the plurality of output electrodes to an output node. As a result, a filtering characteristic of the programmable surface acoustic wave filter can be programmed in a desired format.

Abstract: A power amplifying apparatus for a mobile phone is provided. In the power amplifying apparatus, a power amplifier uses a transistor as a power amplifying device, and a non-volatile memory pre-records the static characteristic measurement data of the transistor. A DC bias current of the transistor is controlled according to transmission power of the power amplifier referring to the static characteristic measurement data, by changing a gate voltage of the transistor, by changing a drain voltage of the transistor with the gate voltage fixed, or by changing both the gate voltage and the drain voltage.

Abstract: An antenna for a mobile telephone, in which a radiation source of the antenna is separated from the user's head while the mobile telephone is in use, to prevent an influence of the radiation waves on the user's head and prevent the non-directional property of the radiation pattern from being degraded. The mobile telephone comprises an antenna body for transmitting and receiving radio waves; a terminal for performing communication based on the radio waves transmitted and received by the antenna body; and a support for maintaining (or supporting) the antenna body to be higher by a predetermined height than the terminal, when the mobile telephone is in use.

Abstract: Compensating for non-linear distortion generated during non-linear high-power amplification in a transmitter after quadrature modulation of a baseband signalby extracting a non-linear distortion component from a non-linearly high-power amplified modulated signal; correcting a phase characteristic such that respective frequency signals in a frequency band of the non-linear distortion component have equal phase delays; quadrature-demodulating the corrected distortion component into a baseband distortion component; and overlapping a phase-inverted distortion component of the quadrature-demodulated baseband distortion component with the baseband signal.

Abstract: A baseband signal communication apparatus includes a transmission unit and a reception unit. The transmission unit superposes a subcarrier on one value of a baseband signal consisting of binary values, modulates a carrier with the baseband signal on which the subcarrier is superposed, and transmits the baseband signal as a transmission signal wave. The reception unit demodulates the baseband signal having the subcarrier superposed thereon by using a demodulator upon reception of the transmission signal wave, extracts the subcarrier from the demodulated signal by using a bandpass filter, and demodulates the baseband signal by causing a detector to detect an envelope of the subcarrier.

Abstract: In a microwave electric power receiver, a microstrip resonator having a line length 1/2 of a wavelength of a microwave to be received is notched to be split at its longitudinally central portion into two portions. A rectification diode is interposed between notched end portions of the microstrip resonator portions to be matched therewith. The diode generates a DC power.

Abstract: A microwave responder resonates or does not resonate with a microwave transmitted from a radio transmitter, and radiates the resonated microwave as a response signal wave. Two microstrip lines are linearly arranged to be separated from each other at a predetermined interval. A diode which is switched between ON and OFF states in response to the response signal is interposed between two end portions of the microstrip lines separated by the predetermined interval, and a distance, between distal ends of the two linearly arranged microstrip lines, which includes an impedance defined by the ON or OFF state of the diode is determined to be 1/2 a wavelength of the microwave.

Abstract: An antenna device shared by three different waves has a single two-stage collinear antenna constituted by half-wave dipole antennas which are adapted for a vehicle telephone signal and are stacked one upon the other. The device allows an AM-FM radio receiver to receive AM and FM broadcast signals via a first coaxial cable and a vehicle telephone transceiver to receive a telephone signal via a second coaxial cable. A first impedance converting circuit is implemented as a field effect transistor and connected to the base end of the antenna for matching the antenna and the first coaxial cable in the event of reception of the AM broadcast signal. A second impedance converting circuit matches the antenna and the first coaxial cable at the time of reception of the FM broadcast signal. The impedance converting circuits convert the input/output impedances of the AM and FM signals.

Abstract: A full duplex transponder system includes an interrogation apparatus and a transponder apparatus. The transponder apparatus includes a reception antenna for receiving an interrogation signal wave whose carrier wave is phase- or frequency-modulated with an interrogation signal, a demodulator for demodulating the interrogation signal from the interrogation signal wave received by the antenna, a rectifier for rectifying the carrier wave of the interrogation signal wave received by the antenna and outputting a DC power used as a drive power source of the transponder apparatus, a multiplier for generating a predetermined harmonic component from the carrier wave of the interrogation signal wave received by the antenna, a modulator for amplitude-modulating the harmonic component with a response signal, and a transmission antenna for transmitting a response signal wave output from the modulator.