초록 ▼

This dual input antenna system has a first input which provides an impedance match over a first range of frequencies and a second input which provides an impedance match over a second range of frequencies. This effectively enables a narrow band antenna to operate and provide a matched condition at t

This dual input antenna system has a first input which provides an impedance match over a first range of frequencies and a second input which provides an impedance match over a second range of frequencies. This effectively enables a narrow band antenna to operate and provide a matched condition at two separate frequency ranges. First and second longitudinal radiating elements are connected at respective ends by an approximate ½wavelength transmission line. The other end of each radiating element is connected by transmission lines to a receive filter and transmit filter, respectively. The receive and transmit filters provide a substantial reactance outside of the respective passbands. The wavelengths of the first and second transmission lines are selected to transform the reactance of each filter into a value which will provide a match condition for the other transmission line at the respective frequency ranges.

대표청구항 ▼

In a portable two-way wireless radio including a receiver which receives signals in a first frequency range, a transmitter which transmits signals in a second frequency range, an antenna having first and second inputs corresponding to the first and second frequency ranges, and a housing in which the

In a portable two-way wireless radio including a receiver which receives signals in a first frequency range, a transmitter which transmits signals in a second frequency range, an antenna having first and second inputs corresponding to the first and second frequency ranges, and a housing in which the antenna is enclosed, the improvement in the antenna comprising: first and second spaced apart radiating elements each having a base end and a distal end; first transmission line means for connecting the base end of said first radiating element to a first filter having a predetermined impedance in the first frequency range and a substantial reactance in the second frequency range, the end of the first transmission line means which is connected to the first filter comprising said first input; second transmission line means for connecting the base end of said second radiating element to a second filter having a predetermined impedance in the second frequency range and a substantial reactance in the first frequency range, the end of the second transmission line means which is connected to the second filter comprising said second input; third transmission line means for connecting the distal ends of said first and second radiating elements, said third transmission line means having an electrical length intermediate the first and second frequency ranges of approximately N/2 wavelengths where N is an integer greater than zero; said first and second transmission line means having characteristic impedances equal to said predetermined impedances of the first and second filters, respectively; said first transmission line means having a length such that the impedance at the base end of said second radiating element in said second frequency range is substantially equal to the characteristic impedance of said second transmission line means; and said second transmission line means having a length such that the impedance at the base end of said first radiating element in said first frequency range is substantially equal to the characteristic impedance of said first transmission line means, whereby the first and second inputs provide impedance matches at the first and second frequency ranges, respectively.