Vertical multiple-input multiple-output wireless antennas
High gain, multi-pattern multiple-input multiple-output (MIMO) antenna systems are disclosed. These systems provide for multiple-polarization and omnidirectional coverage using multiple radios, which may be tuned to the same frequency. The MIMO antenna systems may include multiple high-gain beams arranged (or capable of being arranged) to provide for omnidirectional coverage. These systems provide for increased data throughput and reduced interference without sacrificing the benefits related to size and manageability of an associated access point.
1. A multiple-input multiple-output (MIMO) antenna system, comprising:
a data encoder that encodes data to be transmitted to a receiving node via radio transmission;
a plurality of parallel radios coupled to the data encoder, wherein each of the plurality of parallel radios up-converts the data from the encoders into RF signals;
a MIMO antenna apparatus including a first plurality of antenna elements that each generate a horizontal radiation pattern when selectively coupled to the plurality of parallel radios and a second plurality of antenna elements that each generate a vertical radiation pattern when selectively coupled to the plurality of parallel radios, wherein the plurality set of antenna elements disposed separately from the second plurality of antenna elements, wherein the first plurality of antenna elements are formed as slots on a printed circuit board (PCB), each slot including a plurality of fingers to change resonance and reduce a size of said each slot, and wherein the second plurality of antenna elements are formed as dipoles on the PCB; and
a controller for selectively coupling each of the first and second plurality of antenna elements to one or more of the parallel radios, wherein when two or more of the first plurality of antenna elements are selected, the MIMO antenna apparatus forms a substantially omnidirectional radiation pattern with horizontal polarization, and when two or more of the second plurality of antenna elements are selected, the MIMO antenna apparatus forms a substantially omnidirectional radiation pattern with vertical polarization.
2. The MIMO antenna system of claim 1 , wherein each of the antenna elements is coupled to a radio frequency (RF) switch comprising one or more diodes.
3. The MIMO antenna system of claim 1 , further comprising a plurality of parasitic elements.
4. The MIMO antenna system of claim 3 , further comprising an omnidirectional antenna, wherein the plurality of parasitic elements is positioned around the omnidirectional antenna.
5. The MIMO antenna system of claim 3 , wherein one or more of the plurality of parasitic elements are selected by a switching element to reflect a radiation pattern of the omnidirectional antenna.
6. The MIMO antenna system of claim 3 , wherein one or more of the plurality of parasitic elements are selected by a switching element to redirect a radiation pattern of the omnidirectional antenna.
7. The MIMO antenna system of claim 3 , wherein one or more of the series of parasitic elements are coupled to a switching element, the switching element changing the length of the one or more of the series of parasitic elements thereby making the one or more of the series of parasitic elements transparent to radiation.
8. The MIMO antenna system of claim 7 , wherein the reflection of radiation by the one or more of the series of parasitic elements increases the gain of directional radiation pattern generated by the MIMO antenna apparatus.
9. A multiple-input multiple-output (MIMO) antenna apparatus, comprising:
a substrate defining a vertical space within a housing;
a first plurality of antenna elements selectively coupled to a first radio, wherein the first plurality of antenna elements generates a first directional radiation pattern via an RF signal received from a radio frequency feed port, the first plurality of antenna elements corresponding to a first polarization and located on the substrate, wherein the first plurality of antenna elements are formed as slots on a printed circuit board (PCB), each slot including a plurality of fingers to change resonance and reduce a size of said each slot;
a second plurality of antenna elements selectively coupled to a second radio, wherein the second plurality of antenna elements generates a second directional radiation pattern via an RF signal received from the radio frequency feed port, the second plurality of antenna elements corresponding to a second polarization and located on the substrate, the first plurality of antenna elements and second plurality of antenna elements occupying a vertical space, wherein the first and second radio collectively generate an omnidirectional and diagonally polarized radiation pattern through the selective coupling of the first and second plurality of antenna elements to the radio frequency feed port wherein the second plurality of antenna elements are formed as dipoles on the PCB;
antenna selector elements selectively coupling the first and second plurality of antenna elements to the radio frequency feed port;
a controller for controlling the antenna selector elements to selectively coupling each of the first and second plurality of antenna elements to respective radio, wherein when two or more of the first plurality of antenna elements are selected, the MIMO antenna apparatus forms a substantially omnidirectional radiation pattern with the first polarization, and when two or more of the second plurality of antenna elements are selected, the MIMO antenna apparatus forms a substantially omnidirectional radiation pattern with the second polarization; and
a coupling network, the coupling network including a control bus that receives a control signal for biasing the one or more antenna selector elements.
10. The MIMO antenna apparatus of claim 9 , further comprising one or more parasitic antenna elements located on the substrate and coupled to the coupling network, the coupling network biasing the one or more parasitic antenna elements.
11. The MIMO antenna apparatus of claim 10 , wherein the one or more parasitic antenna elements are biased to operate as a reflector.
12. The MIMO antenna apparatus of claim 10 , wherein the one or more parasitic antenna elements are biased to operate as a director.
13. The MIMO antenna apparatus of claim 10 , wherein the one or more parasitic elements are selectively coupled to one another via a switching network, the switching network receiving a control signal for coupling one or more of the parasitic elements to one another, thereby changing the length of the one or more parasitic elements and influencing the directional radiation pattern emitted by the first radio or the second radio.
14. The MIMO antenna apparatus of claim 9 , wherein the coupling network includes a series of diodes for selectively coupling antenna elements to the radio frequency feed port.
15. The MIMO antenna apparatus of claim 14 , wherein one or more of the diodes from the series of diodes is a p-type, intrinsic, n-type (PIN) diode.
16. The MIMO antenna apparatus of claim 9 , wherein the coupling network includes a series of gallium arsenide field-effect transistors (GaAs FETs) for selectively coupling the antenna elements to the radio frequency feed port.
17. The MIMO antenna apparatus of claim 9 , wherein the coupling network further includes one or more light emitting diodes (LEDs) placed in circuit with an antenna element such that the selection of an associated antenna element illuminates the LED.
18. The MIMO antenna apparatus of claim 9 , wherein the directional radiation pattern of the first radio has a horizontal polarization and the directional radiation pattern of the second radio has a vertical polarization.
19. The MIMO antenna apparatus of claim 9 , wherein the directional radiation pattern of the first radio and the directional radiation pattern of the second radio are opposite one another.
20. The MIMO antenna apparatus of claim 9 , wherein the directional radiation pattern of the first radio and the directional radiation pattern of the second radio partially overlap one another.
21. The MIMO antenna apparatus of claim 9 , wherein the directional radiation pattern of the first radio and the directional radiation pattern of the second radio form a substantially omnidirectional radiation pattern.