Dual band notch antenna for portable radiotelephones

A portable radio transceiver comprising:

• receiver circuitry which receives signals in a first frequency range;
• transmitter circuitry which transmits signals in a second frequency range;
• an elongated housing of substantially rectangular shape having a length L, width W less than L, and depth D less than W, said housing being comprised of conductive material and containing said transmitter circuitry and said receiver circuitry therein, said housing having top and bottom portions located at opposite ends of the major longitudinal axis of said housing;
• and
• notch antenna means for radiating radio frequency waves, said notch antenna means constructed in said bottom portion of said housing and centered along said major longitudinal axis of said housing and positioned such that a plane passing through the notch is perpendicular to the major surface plane of said housing,
• whereby said notch antenna means radiates vertically polarized E-field waves in a substantially omnidirectional radiation pattern when said transceiver is positioned in free space such that said longitudinal axis is approximately 30 degrees to the horizontal.

A portable radio transceiver comprising:

• receiver circuitry which receives signals in a first frequency range, s id receiver circuitry including a first filter having a predetermined impedance in said first frequency range and a substantial reactance in a second frequency range;
• transmitter circuitry which transmits signals in said second frequency range, said transmitter circuitry including a second filter having a predetermined impedance in said second frequency range and a substantial reactance in said first frequency range;
• an elongated housing comprised of conductive material and containing said transmitter circuitry and said receiver circuitry therein, said housing having top and bottom portions located at opposite ends of the major longitudinal axis of said housing;
• notch antenna means for radiating and receiving radio frequency waves, said notch antenna means comprising an open-ended notch aperture constructed in said bottom portion of said conductive housing and centered along said major longitudinal axis of said housing, said notch antenna means having first and second antenna terminals corresponding to said first and second frequency ranges, respectively;
• first transmission line means for coupling said notch antenna first antenna terminal to said first filter, the end of said first transmission line means which is connected to said first filter comprising a first filter port;
• second transmission line means for coupling said notch antenna second antenna terminal to said second filter, the end of said second transmission line means which is connected to said second filter comprising a second filter port,
• said first and second transmission line means having characteristic impedances equal to said predetermined impedances of said first and second filters, respectively,
• said first transmission line means having a length such that the impedance at said notch antenna second antenna terminal 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 said notch antenna first antenna terminal in said first frequency range is substantially equal to the characteristic impedance of said first transmission line means,
• whereby said first and second filter ports provide impedance matches at said first and second frequency ranges, respectively.