Abstract: A compact antenna enabling to produce high gain is based on an antenna main body is constructed in such a way that a plurality of resonance sections, each having parallel-connected respective inductance sections and capacitance sections, are electrically connected in series, and a frequency adjusting capacitance section is connected electrically in series between a ground section at the ground potential and an exit end of the antenna main body. The resonance sections are constructed so that that the characteristic frequency curves overlap one another at least in the width portion to enable the antenna man body as a whole to resonate at substantially one resonance frequency, which is higher than the normal vibration frequency at which each resonance section resonates.

Abstract: An antenna is provided to improve the gain and to eliminate various negative effects caused by a surrounding environment in which the antenna is mounted, such as the effects caused by neighboring metal plates and the like, while providing an antenna structure to facilitate its assembly into various communication devices. The antenna emitting radio waves at a center frequency has an antenna main body and a grounding line section connected to the ground-side of the coaxial cable for supplying power to the antenna main body. The grounding line section starts from a reference point and extends in a loop so as to surround the antenna main body, and portions of the conductor line are severed so as to provide a first end terminal and a second end terminal so that the length of the conductor line from the reference point to the first end terminal corresponds to one quarter of a wavelength of the center frequency or its integral multiple.

Abstract: An antenna of a compact size enables to raise the inductance value of the resonance section and produce high gain. The antenna is constructed by connecting resonance sections and in series, in which each antenna element has an inductance section and a capacitance section connected electrically in parallel, and each inductance section has a conductor shaped in a square shape to circle the respective coil axes, and the opening sections formed at respective ends of the coil sections are contained in respective planes that are oriented at an angle to the coil axes.

Abstract: A high gain antenna of a compact external dimensions enables various devices for processing radio signals to include the antenna within the internal circuitry, so that there is no need to extend the antenna and avoid a danger of breaking the antenna, and the external appearance of the device is improved. The antenna is constructed by connecting antenna elements and in series, in which each antenna element has an inductance sections and a capacitance sections connected in parallel in such a way that magnetic fields generated by the inductance sections are oriented to intersect with one another so as to increase the signal gain.

Abstract: A compact antenna enabling to produce high gain is based on an antenna main body is constructed in such a way that a plurality of resonance sections, each having parallel-connected respective inductance sections and capacitance sections, are electrically connected in series, and a frequency adjusting capacitance section is connected electrically in series between a ground section at the ground potential and an exit end of the antenna main body. The resonance sections are constructed so that that the characteristic frequency curves overlap one another at least in the width portion to enable the antenna man body as a whole to resonate at substantially one resonance frequency, which is higher than the normal vibration frequency at which each resonance section resonates.

Abstract: An antenna is provided to improve the gain and to eliminate various negative effects caused by a surrounding environment in which the antenna is mounted, such as the effects caused by neighboring metal plates and the like, while providing an antenna structure to facilitate its assembly into various communication devices. The antenna emitting radio waves at a center frequency has an antenna main body and a grounding line section connected to the ground-side of the coaxial cable for supplying power to the antenna main body. The grounding line section starts from a reference point and extends in a loop so as to surround the antenna main body, and portions of the conductor line are severed so as to provide a first end terminal and a second end terminal so that the length of the conductor line from the reference point to the first end terminal corresponds to one quarter of a wavelength of the center frequency or its integral multiple.

Abstract: An antenna of a compact size enables to raise the inductance value of the resonance section and produce high gain. The antenna is constructed by connecting resonance sections and in series, in which each antenna element has an inductance section and a capacitance section connected electrically in parallel, and each inductance section has a conductor shaped in a square shape to circle the respective coil axes, and the opening sections formed at respective ends of the coil sections are contained in respective planes that are oriented at an angle to the coil axes.

Abstract: A high gain antenna of a compact external dimensions enables various devices for processing radio signals to include the antenna within the internal circuitry, so that there is no need to extend the antenna and avoid a danger of breaking the antenna, and the external appearance of the device is improved. The antenna is constructed by connecting antenna elements and in series, in which each antenna element has an inductance sections and a capacitance sections connected in parallel in such a way that magnetic fields generated by the inductance sections are oriented to intersect with one another so as to increase the signal gain.

Abstract: A digital communication method and system wherein in response to input 3-bit data, a phase and amplitude of a carrier signal are controlled so that a symbol at a given time is located at one of allowed signal points depending on the content of the symbol. The allowed signal points include six signal points where a phase shift equal to .+-..pi./4, .+-.2.pi./4, or .+-.3.pi./4 occurs relative to the signal point at which the immediately previous symbol was located and where the amplitude is equal to a first level, and also include two signal points where a phase shift equal to .+-.2.pi./4 occurs relative to the signal point at which the immediately previous symbol was located and where the amplitude is equal to a second level lower than the first level. The digital communication method and system allows for a transmitter which does require a high-performance power amplifier, and a simplified receiver circuit.