An example method of designing a multi-band antenna includes specifying a first portion of the multi-band antenna in a tangible medium, where the first portion corresponds to an existing design of a single-band monopole antenna for operating in a first frequency band, and specifying in the tangible medium a second portion of the multi-band antenna that is added to the first portion, where the second portion includes a dipole parasitic resonator that is resonant in a second frequency band.
1. A multi-band antenna comprising:
a first portion that corresponds to a monopole antenna operable in a first frequency band, the first portion comprising:
a first segment connected to a ground plane portion and extending away from the ground plane portion,
a second segment connected to the first segment and extending away therefrom in a first direction that is approximately parallel to the ground plane portion, and
a third segment connected to the second segment and extending away therefrom in a second direction that is away from the ground plane portion, a signal source being connected to the third segment; and
a second portion connected to the first portion as a dipole parasitic resonator that is resonant in a second frequency band, the second portion comprising a fourth segment that:
is connected to the second segment at approximately a longitudinal center of the fourth segment,
faces the third segment, and
has a longitudinal axis oriented along a third direction that is approximately perpendicular to the first direction.
2. The multi-band antenna of claim 1 ,
wherein a maximum height of the multi-band antenna above the ground plane is less than or equal to 11 mm.
3. The multi-band antenna of claim 1 ,
wherein a VSWR of the multi-band antenna is less than 2 to 1 throughout the first and second frequency bands.
4. The multi-band antenna of claim 1 ,
wherein the first frequency band includes a 5 GHz frequency band, and
the second frequency band includes a 2 GHz frequency band.
5. The multi-band antenna of claim 1 ,
wherein the second segment is a shunt matching inductor that provides a parallel inductance to cancel a shunt capacitance realized by the first portion.
6. A method of forming a specification of a multi-band antenna, comprising:
specifying a first portion of the multi-band antenna in a tangible medium, the first portion corresponding to an existing design of a single-band monopole antenna for operating in a first frequency band, the existing design comprising:
a first segment connected to a ground plane portion and extending away from the ground plane portion,
a second segment connected to the first segment and extending away therefrom in a first direction that is approximately parallel to the ground plane portion, and
a third segment connected to the second segment and extending away therefrom in a second direction that is away from the ground plane portion, a signal source being connected to the third segment; and
specifying in the tangible medium a second portion of the multi-band antenna that is added to the first portion, the second portion comprising a fourth segment that acts as a dipole parasitic resonator that is resonant in a second frequency band and is connected to the second segment of the first portion.
7. The method of claim 6 ,
wherein a maximum height of the multi-band antenna above a ground plane is less than or equal to 11 mm.
8. The method of claim 6 ,
wherein the fourth segment:
is connected to the second segment at approximately a longitudinal center of the fourth segment,
faces the third segment, and
has a longitudinal axis oriented along a third direction that is approximately perpendicular to the first direction.
9. The method of claim 6 ,
wherein specifying the second portion of the multi-band antenna includes specifying that a geometry of the fourth segment and a distance between the fourth segment and the third segment are such that a VSWR of the multi-band antenna is less than 2 to 1 throughout the first and second frequency bands and a radiation pattern of the multi-band antenna is not significantly different from a radiation pattern of an antenna comprising the first portion without the second portion.
10. The method of claim 6 ,
wherein the first frequency band includes a 5 GHz frequency band and the second frequency band includes a 2 GHz frequency band.
11. A method of manufacturing a multi-band antenna, comprising:
forming a first portion of the multi-band antenna that, upon being formed, is a single-band monopole antenna that is operable in a first frequency band, the first portion including:
a first segment connected to a ground plane portion and extending away from the ground plane portion,
a second segment connected to the first segment and extending away therefrom in a first direction that is approximately parallel to the ground plane portion, and
a third segment connected to the second segment and extending away therefrom in a second direction that is away from the ground plane portion, a signal source being connected to the third segment;
forming a second portion of the multi-band antenna that is initially separate from the first portion and includes a fourth segment; and
connecting the fourth segment to the second segment such that the fourth segment acts as a dipole parasitic resonator that is resonant in a second frequency band.
12. The method of claim 11 ,
wherein a maximum height of the multi-band antenna above the ground plane is less than or equal to 11 mm.
13. The method of claim 11 ,
wherein connecting the fourth segment to the second segment includes connecting the fourth segment to the second segment at approximately a longitudinal center of the fourth segment such that the fourth segment:
faces the third segment, and
has a longitudinal axis oriented along a third direction that is approximately perpendicular to the first direction.
14. The method of claim 11 ,
wherein, upon the fourth segment being connected to the second segment, a geometry of the fourth segment and a distance between the fourth segment and the third segment are such that a VSWR of the multi-band antenna is less than 2 to 1 throughout the first and second frequency bands and a radiation pattern of the multi-band antenna is not significantly different from a radiation pattern of an antenna comprising the first portion without the second portion.
15. The method of claim 11 ,
wherein the first frequency band includes a 5 GHz frequency band and the second frequency band includes a 2 GHz frequency band.