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.

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.

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.

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.

Abstract: An antenna (100) having an antenna structure is provided. The antenna structure is formed of a first section (102) and a second section (104). The first section is formed of a rolled conductive strip forming a helical coil having non-overlapping successive turns, and the second section (104) is formed of a wire spring coil having non-overlapping successive turns. The antenna (100) provides multi-band capability.

Abstract: An antenna (100) having an antenna structure is provided. The antenna structure is formed of a first section (102) and a second section (104). The first section is formed of a rolled conductive strip forming a helical coil having non-overlapping successive turns, and the second section (104) is formed of a wire spring coil having non-overlapping successive turns. The antenna (100) provides multi-band capability.

Abstract: A hybrid antenna structure allows the antenna to be used internally or mostly internally in a portable radio communication device operating in the VHF range. The hybrid antenna structure includes a switching circuit that connects an RF circuit to one of several points along the length of a wrapped conductor element, depending on the selected operating frequency. An inductive matching tail element is adjustably tuned to match the selected tap point on the wrapped conductor for the selected operating frequency.

Abstract: A hybrid antenna structure allows the antenna to be used internally or mostly internally in a portable radio communication device operating in the VHF range. The hybrid antenna structure includes a switching circuit that connects an RF circuit to one of several points along the length of a wrapped conductor element, depending on the selected operating frequency. An inductive matching tail element is adjustably tuned to match the selected tap point on the wrapped conductor for the selected operating frequency.