Dual contra-wound helical antenna for a communication device

    公开(公告)号:US10910725B2

    公开(公告)日:2021-02-02

    申请号:US16079117

    申请日:2016-05-16

    Abstract: An antenna is provided having a primary helical coil (102) and a secondary helical coil (104) contra-wound relative to the primary helical coil. Switchable coupling between the coils allows the antenna response to switch from lower to higher frequency responses within the same Ultra High Frequency (UHF) band. A bandwidth of the same physical length antenna can be increased up to twice the bandwidth or for a fixed bandwidth, the antenna length can be shortened. For the high frequency band, when the secondary helix is disconnected from the primary helix, the primary coil operates as a interferer notch out to improve interference rejection, to reject unwanted signals from nearby radios transmitting in frequencies separated by duplex spacing, such as Terrestrial Trunked Radio (TETRA) and cellular Global System for Mobile (GSM) communication bands.

    Dual-feedback amplifier limiter
    2.
    发明授权

    公开(公告)号:US10581383B2

    公开(公告)日:2020-03-03

    申请号:US15779176

    申请日:2015-12-17

    Abstract: A method and apparatus for a dual-feedback, amplifier limiter for providing a conditioned radio-frequency signal. The dual-feedback, amplifier limiter includes an input that receives a radio-frequency signal and a stacked amplifier including an input node coupled to the input, an output node, a first transistor configured as a common-base amplifier, and a second transistor configured as a common-emitter amplifier. The dual-feedback, amplifier limiter further includes an output coupled to the output node of the stacked amplifier. The output provides the conditioned radio-frequency signal. The dual-feedback, amplifier limiter further includes a radio-frequency feedback circuit coupled to the stacked amplifier. The radio-frequency feedback circuit includes a passive radio-frequency dependent reactive element in series with a radio-frequency feedback circuit resistor. The dual-feedback, amplifier limiter further includes an envelope control feedback circuit coupled to the stacked amplifier and including a current mirror and a reactive element loop filter.

    DUAL-FEEDBACK AMPLIFIER LIMITER
    3.
    发明申请

    公开(公告)号:US20180351514A1

    公开(公告)日:2018-12-06

    申请号:US15779176

    申请日:2015-12-17

    Abstract: A method and apparatus for a dual-feedback, amplifier limiter for providing a conditioned radio-frequency signal. The dual-feedback, amplifier limiter includes an input that receives a radio-frequency signal and a stacked amplifier including an input node coupled to the input, an output node, a first transistor configured as a common-base amplifier, and a second transistor configured as a common-emitter amplifier. The dual-feedback, amplifier limiter further includes an output coupled to the output node of the stacked amplifier. The output provides the conditioned radio-frequency signal. The dual-feedback, amplifier limiter further includes a radio-frequency feedback circuit coupled to the stacked amplifier. The radio-frequency feedback circuit includes a passive radio-frequency dependent reactive element in series with a radio-frequency feedback circuit resistor. The dual-feedback, amplifier limiter further includes an envelope control feedback circuit coupled to the stacked amplifier and including a current mirror and a reactive element loop filter.

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