Dual antenna capable of transmitting and receiving circularly polarized electromagnetic wave and linearly polarized electromagnetic wave

• US 6,879,294 B2
• Filed: 04/17/2003
• Issued: 04/12/2005
• Est. Priority Date: 04/17/2002
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Yuanzhu, Dou
• Primary Examiner(s): Vannucci, James
• Application Number:
  US10/417,491
• Publication Number:
  US 20030197651A1
• Time in Patent Office: 726 Days
• Field of Search: 343/711, 343/713, 343/700.MS, 343/725, 343/900, 343/904
• US Class Current: 343/725
• CPC Class Codes: H01Q 1/12 Supports; Mounting means
• CPC Class Codes: H01Q 1/3275 mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 9/0428 radiating a circular polarised wave

Abstract

A direction of a power feed patch relative to a rod-shaped antenna is set so that a short axis thereof substantially orthogonally crosses a plane containing an intersection between the short axis and a long axis of the power feed patch of a patch antenna and an axis of the rod-shaped antenna. As a plane of polarization of a linearly polarized electromagnetic wave radiated from the rod-shaped antenna is thereby caused to substantially coincide with a direction of the long axis of the power feed patch and to substantially orthogonally cross a direction of the short axis, even if a powerful wave of a higher frequency than a desired frequency to be received by the patch antenna and difficult to be removed by a band pass filter of a low-noise amplifier circuit is radiated from the rod-shaped antenna, field components of the high frequency electromagnetic wave in the direction of the short axis will become virtually zero.

Claims

1. A dual antenna comprising:

a patch antenna having a power feed patch disposed over a dielectric substrate and configured to transmit and receive a circularly polarized electromagnetic wave; and

a rod-shaped antenna erected a predetermined distance from the patch antenna and configured to transmit and receive a linearly polarized electromagnetic wave,

wherein the power feed patch has a short axis and a long axis, the short axis having a resonance length smaller than that of the long axis, the short axis and long axis orthogonally crossing each other, and

wherein a direction of the power feed patch relative to the rod-shaped antenna is set so that the short axis substantially orthogonally crosses a plane, the plane containing an intersection between the short axis and long axis and an axis of symmetry of the rod-shaped antenna.

2. The dual antenna according to claim 1, wherein an angle formed by the plane and the short axis is set within a range of 85 degrees to 95 degrees.

3. The dual antenna according to claim 1, wherein the rod-shaped antenna is inclined with respect to the plane containing the intersection between the short axis and long axis and the axis of symmetry of the rod-shaped antenna.