Dual orthogonal monopole antenna system

An antenna system, comprising:

• a first dielectric layer having an outside surface and an inside surface;
• a second dielectric layer having an outside surface and an inside surface, the second dielectric layer generally parallel to the first dielectric layer;
• a ground plane conductive film between the inside surfaces of the first and second dielectric layers;
• a first monopole antenna on the outside surface of the first dielectric layer;
• a second monopole antenna on the outside surface of the second dielectric layer, and arranged generally orthogonally to the first monopole antenna;
• and
• a feed circuit coupled to the first and second monopole antennas to connect the first and second monopole antennas to a host system.

An antenna system for a communications device, the communications device including a circuit board with circuitry providing communications functions and a shield, the shield being coupled to the circuit board and being positioned with respect to the circuit board to shield the circuitry on the circuit board with respect to electromagnetic radiation, comprising:

• a first dielectric layer coupled to the circuit board and extending outside the shield, the first dielectric layer having an outside surface and an inside surface;
• a second dielectric layer coupled to the circuit board and extending outside the shield, the second dielectric layer having an outside surface and an inside surface;
• a ground plane conductive film coupled to the circuitry and extending outside the shield between the inside surfaces of the first and second dielectric layers;
• a first monopole antenna extending outside the shield, the first monopole antenna comprising an impedance matched microstrip on the outside surface of the first dielectric layer;
• a second monopole antenna extending outside the shield, the second monopole antenna comprising an impedance matched microstrip on the outside surface of the second dielectric layer, and arranged generally orthogonally to the first monopole antenna;
• and
• a feed circuit to connect the first and second monopole antennas to the shielded circuitry.

An antenna system for a communication device, comprising:

• a first dielectric layer having an outside surface and an inside surface;
• a second dielectric layer having an outside surface and an inside surface, the second dielectric layer generally parallel to the first dielectric layer;
• a ground plane conductive film between the inside surfaces of the first and second dielectric layers;
• a first monopole antenna on the outside surface of the first dielectric layer;
• a second monopole antenna on the outside surface of the second dielectric layer, the second monopole antenna arranged generally orthogonally to the first monopole antenna;
• a feed circuit coupled to the first and second monopole antennas;
• and
• a switch circuit and a switch driver, coupled to the feed circuit, which periodically selects the first monopole antenna and the second monopole antenna with a period greater than a characteristic reception interval for packets of data received at the antenna system, independent of other processing in the communications device.