摘要:
A dual band antenna comprising structurally different antenna elements and having common feed. The antenna includes a ground plane, a radiating element and an arm extending from the radiating element. In a first operating mode energy is radiated from the arm, the radiating element and the ground plane. In a second operating mode energy is radiated from the radiating element and the ground plane. Thus the antenna operates in two modes with two different resonant frequencies.
摘要:
An antenna for transmitting and receiving radio frequency energy. The antenna comprises a conductive radiator comprising a first and a second conductive region for providing a first and a second current path length. A feed conductor and a ground conductor operate as meanderline (or slow wave) elements to provide an electrical length longer than a physical length.
摘要:
A radio frequency identification tag attached to an object and comprising an antenna and an integrated circuit for providing object information to a separate reader. The antenna further comprises a pair of meanderline transmission lines each terminated at a first end for conductive connection to the integrated circuit. A shorting bar connected between the pair of meanderline transmission lines at the first ends is operative to match an antenna impedance with an integrated circuit impedance.
摘要:
A radio frequency transmitting and receiving apparatus comprising an antenna further comprising a plurality of antenna segments. Each segment exhibits a different electrical length and certain of the segments are capacitively coupled to establish a resonant frequency for each segment. In one embodiment, the certain segments comprise a plurality of concentric arcuate conductive elements connected to a signal terminal and a ground plane.
摘要:
A communications apparatus comprising a first antenna, a first serial configuration of a first power amplifier and a first matching network, a second serial configuration of a second power amplifier and a second matching network, a switching element for switchably selecting the first or the second serial configuration for supplying a signal to the first antenna, the first and the second power amplifiers supplying a respective first signal of a first power and a second signal of a second power different than the first power to the first antenna for transmitting and the first and the second matching networks presenting respective first and second impedances to the respective first and second power amplifiers, the first and the second impedances responsive respectively to a power-related parameter of the first and the second signals.
摘要:
An antenna for a communications device having configurable elements controlled to modify an antenna impedance and/or an antenna resonant frequency to improve performance of the communications device. The antenna impedance is controlled to substantially match to an output impedance of a power amplifier that supplies the antenna with a signal for transmission. The antenna resonant frequency is controlled to overcome the effects of various operating conditions that can detune the antenna or in response to an operable frequency band.
摘要:
An antenna for a communications device having configurable elements controlled to modify an antenna impedance and/or an antenna resonant frequency to improve performance of the communications device. The antenna impedance is controlled to substantially match to an output impedance of a power amplifier that supplies the antenna with a signal for transmission. The antenna resonant frequency is controlled to overcome the effects of various operating conditions that can detune the antenna or in response to an operable frequency band.
摘要:
An antenna operative in a plurality of frequency bands. The antenna comprises first and second high band resonators, a resonating meanderline and a counterpoise. A ground return conductively couples one or more regions of the counterpoise to the meanderline. One or more of the first resonating element, the second resonating element and the resonating meanderline are coupled by magnetic and/or capacitive coupling to provide operation in the plurality of frequency bands.
摘要:
A system and method are described in which space-time coding techniques are used to transmit and receive multiple data streams within a near vertical incidence skywave (“NVIS”) communication system. Within the NVIS communication system, multiple independent data streams may be transmitted from a transmitting station at a high radiation angle, approaching or reaching 90 degrees. The data streams are reflected off of the ionosphere of the earth and received by one or more receiving stations. In one embodiment, the space-time coding techniques are multiple-input multiple-output (“MIMO”) signal communication techniques.
摘要:
An antenna system operative with a communications device for receiving a radio frequency signal, wherein the communications device produces a first control signal representing a frequency of a received signal. The antenna system comprises an antenna structure for receiving the radio frequency signal, the antenna structure comprising tunable elements for controlling a resonant frequency of the antenna structure; a decoder responsive to the first control signal for producing a second control signal and a switch matrix responsive to the second control signal for configuring one or more of the tunable elements to control the resonant frequency responsive to the frequency of the received signal.