Antenna array with asymmetric antenna elements

• US 9,509,061 B2
• Filed: 10/05/2015
• Issued: 11/29/2016
• Est. Priority Date: 11/05/2013
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Inventors: Koch, Michael J.
• Primary Examiner(s): Kim, Ahshik
• Application Number:
  US14/875,001
• Publication Number:
  US 20160134025A1
• Time in Patent Office: 421 Days
• Field of Search: 235/444, 235/495, 343/700.MS, 343/893
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10326 the antenna being of the very-near field type, e.g. capacitive
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 21/0006 Particular feeding systems
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/205 providing an omnidirectional coverage turnstile aerials H01Q21/26
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H01Q 9/0428 radiating a circular polarised wave
• CPC Class Codes: H01Q 9/0435 using two feed points
• CPC Class Codes: H01Q 9/0442 with particular tuning means

Abstract

An RFID reader is provided that includes an antenna array comprising multiple antenna elements circumferentially distributed around a longitudinal axis of the antenna array. Each antenna element includes multiple patch elements disposed above one or more underlying substrates, wherein the patch elements of each antenna element are disposed on an outer side of the antenna element. Further, one or more of the antenna elements is an asymmetric antenna element, wherein a first end of the asymmetric antenna element is wider than a second, opposite end of the asymmetric antenna element, wherein a first patch element disposed proximate to the first end of the asymmetric antenna element is larger than a second patch element disposed proximate to the second end of the asymmetric antenna element, and wherein a resonant frequency associated with the first patch element is approximately the same as a resonant frequency associated with the second patch element.

Claims

1. An asymmetric antenna element of comprising:

a substrate;

a plurality of patch elements disposed above the substrate; and

wherein a first end of the antenna element is wider than a second, opposite end of the antenna element, wherein a first patch element disposed proximate to the first end of the asymmetric antenna element is larger than a second patch element disposed proximate to the second end of the asymmetric antenna element, and wherein a resonant frequency associated with the first patch element of the asymmetric antenna element is approximately the same as a resonant frequency associated with the second patch element of the asymmetric antenna element.

2. The antenna element of claim 1, wherein each of the first and second patch elements is configured so that it may be one of horizontally polarized, vertically polarized, or circularly polarized.