Antenna arrangement and a module and a radio communications apparatus having such an arrangement
An antenna arrangement for a radio communications apparatus such as a mobile phone, comprises a substantially planar patch conductor having a first feed connection point for connection to radio circuitry and a second feed connection point for connection to a ground plane, a first, differential slot in the patch conductor between the first and second connection points and a second, dual band slot located in the patch conductor outside the area between the first and second connection points. The length of the first slot is greater than a quarter wavelength, and provides a third resonant frequency increasing the bandwidth of the antenna. The width of the patch conductor between the first and the second slots is selected to obtain a low impedance transformation and thereby a low antenna resistance causing detuning the antenna. A user holding the phone increases the antenna resistance thereby tuning the antenna.
1. An antenna arrangement comprising a substantially planar patch conductor having a first feed connection point for connection to radio circuitry and a second feed connection point or connection to a ground plane, a first, differential slot in the patch conductor between the first and second connection points and a second, dual band slot located in the patch conductor outside the area between the first and second connection points, wherein the length of the first slot is such as to provide an additional resonance, and the width of the patch conductor between the first and the second slots is selected to give an impedance less than a system impedance.
2. An antenna arrangement as claimed in claim 1 , wherein the length of the first slot is greater than a quarter wavelength.
3. An antenna arrangement as claimed in claim 1 , wherein the length of the first slot is such that the additional resonance combines with an adjacent resonance.
4. A module comprising a printed circuit board providing a ground plane, radio circuitry mounted on the PCB, and an antenna arrangement, the antenna arrangement comprising a substantially planar patch conductor having a first feed connection point for connection to the radio circuitry and a second feed connection point for connection to the ground plane, a first, differential slot in the patch conductor between the first and second connection points and a second, dual band slot located in the patch conductor outside the area between the first and second connection points, wherein the length of the first slot is such as to provide an additional resonance, and the width of the patch conductor between the first and the second slots is selected to give an impedance less than a system impedance.
5. A module as claimed in claim 4 , wherein the length of the first slot is greater than a quarter wavelength.
6. A module as claimed in claim 4 , wherein the length of the first slot is such that the additional resonance combines with an adjacent resonance.
7. A radio communications apparatus comprising a casing containing a printed circuit board providing a ground plane, radio circuitry mounted on the printed circuit board, and an antenna arrangement, the antenna arrangement comprising a substantially planar patch conductor having a first feed connection point for connection to the radio circuitry and a second feed connection point for connection to the ground plane, a first, differential slot in the patch conductor between the first and second connection points and a second, dual band slot located in the patch conductor outside the area between the first and second connection points, wherein the length of the first slot is such as to provide an additional resonance, and the width of the patch conductor between the first and the second slots is selected to give an impedance less than a system impedance.