ANTENNAS INCLUDING A PARASITIC ELEMENT COUPLED TO AN ACTIVE ELEMENT
Antennas are provided herein that include a parasitic element that is coupled to an active element and a ground plane. In some embodiments, the active element is inside an outline provided by a combination of the parasitic element and the ground plane. Moreover, the active element and the parasitic element are, in some embodiments, on opposite surfaces, respectively, of a printed circuit board.
1 . An antenna comprising:
a ground plane;
a parasitic element coupled to the ground plane; and
an active element having a vertical portion and a horizontal portion that are each inside an outline provided by a combination of the parasitic element and the ground plane,
wherein the parasitic element is coupled to the active element.
2 . The antenna of claim 1 , wherein the parasitic element has a symmetrical shape.
3 . The antenna of claim 2 , wherein the active element and the parasitic element comprise T-shaped and Pi-shaped radiating elements, respectively.
4 . The antenna of claim 1 , wherein the active element is centered between vertical legs of the outline.
5 . The antenna of claim 1 ,
wherein the parasitic element comprises first and second vertical portions, and
wherein the vertical portion of the active element is closer to the second vertical portion of the parasitic element than to the first vertical portion of the parasitic element.
6 . The antenna of claim 1 , further comprising a substrate having a first surface and a second surface that is opposite the first surface,
wherein the parasitic element and the active element are on the first surface of the substrate and the second surface of the substrate, respectively.
7 . The antenna of claim 6 ,
wherein the ground plane comprises a ground plane of a printed circuit board (PCB), and
wherein the substrate is on a surface of the PCB.
8 . The antenna of claim 7 ,
wherein the PCB comprises first and second plated through hole (PTH) vias therein, and
wherein the parasitic element comprises first and second vertical portions that are coupled to the ground plane through the first and second PTH vias, respectively.
9 . A monopole antenna comprising:
a parasitic element having a horizontal portion and first and second vertical portions; and
an active element having a vertical portion and a horizontal portion,
wherein the parasitic element of the monopole antenna is inductively and/or capacitively coupled to the active element of the monopole antenna.
10 . The monopole antenna of claim 9 , wherein the parasitic element is both capacitively coupled and inductively coupled to the active element.
11 . The monopole antenna of claim 10 ,
wherein the horizontal portion of the parasitic element is capacitively coupled to the horizontal portion of the active element, and
wherein at least one of the first and second vertical portions of the parasitic element is inductively coupled to the vertical portion of the active element.
12 . An antenna comprising an active portion and a parasitic portion that are on opposite surfaces, respectively, of a first printed circuit board (PCB).
13 . The antenna of claim 12 , further comprising a second PCB having a surface that has the first PCB thereon.
14 . The antenna of claim 13 , wherein the opposite surfaces of the first PCB are perpendicular to the surface of the second PCB.
15 . The antenna of claim 13 ,
wherein the second PCB comprises first and second plated through hole (PTH) vias therein, and
wherein the parasitic portion of the antenna is grounded through the first and second PTH vias.
16 . The antenna of claim 13 ,
wherein the parasitic portion of the antenna comprises a horizontal portion having a first length, and
wherein a second length from a top of the horizontal portion to the surface of the second PCB is shorter than the first length.
17 . The antenna of claim 13 , wherein the parasitic portion of the antenna comprises:
a horizontal portion extending a first distance in a direction parallel to the surface of the second PCB; and
first and second vertical portions that are spaced apart from each other by a second distance that is shorter than the first distance.
18 . The antenna of claim 12 , wherein the parasitic portion of the antenna is both capacitively coupled and inductively coupled to the active portion of the antenna.
19 . The antenna of claim 12 , wherein the active portion of the antenna is a straight line on the first PCB.
20 . The antenna of claim 12 , wherein the active portion of the antenna comprises a horizontal portion and a vertical portion.