# US 7,746,276 B2 · Microstrip multi-band composite antenna > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,746,276 B2 - Document ID: US7746276B2 - Status: Granted - Kind: B2 - Application number: 11/719,246 - Filed: 2006-02-02 - Published: 2009-03-26 - Granted: 2010-06-29 - Earliest claimed: 2006-02-02 - Assignees: Sandbridge Technologies, Inc. - Inventors: Emanoil Surducan; Daniel Iancu; John Glossner - Web page: https://patentgrep.com/patent/US7746276B2 ## CPC - H01Q 9/28: Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines (waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00) - H01Q 1/38: formed by a conductive layer on an insulating support {(patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142)} - H01Q 9/285: {Planar dipole (H01Q9/065 takes precedence; patch antenna H01Q9/0407)} - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract The multi-band antenna structure includes a first antenna having a band width about a middle frequency and a second antenna spaced and electrically isolated from the antenna. Ends of the second antenna are shorted to each other and the antenna floats electrically. The first and second antennas are planar and superimposed in parallel planes. At least two layers of dielectric material of a thickness is between the two antennas. A third layer of dielectric material of a third thickness is between the two antennas. ## Claims ### Claim 1 A multi-band antenna structure comprising: a first antenna having a first band width about a first middle frequency; a second antenna spaced and electrically isolated from the first antenna; and an electrically floating split ring resonator spaced apart from the first and second antennas, wherein, ends of the second antenna are shorted to each other and the second antenna floats electrically, and wherein the antenna structure has a plurality of bandwidths each about a respective middle frequency of the antenna structure. ### Claim 2 (depends on 1) The antenna structure of claim 1, wherein the first and second antennas are planar and superimposed upon one another in parallel planes. ### Claim 3 (depends on 2) The antenna structure of claim 2, including at least first and second layers of dielectric material of a first and second thickness respectively disposed between the two antennas. ### Claim 4 (depends on 3) The antenna structure of claim 3, including a third layer of dielectric material of a third thickness disposed between the two antennas. ### Claim 5 (depends on 4) The antenna structure of claim 4, wherein the total thickness of the three layers of dielectric material is less than the quarter wavelength of a lowest middle frequency of the antenna structure. ### Claim 6 (depends on 4) The antenna structure of claim 4, wherein the first thickness of the first layer adjacent the first antenna is greater than the third thickness of the third layer adjacent the second antenna, and the first and third layers have the same permittivity. ### Claim 7 (depends on 6) The antenna structure of claim 6, wherein the second thickness of the second layer between the first and third layers is greater than the first thickness of the first layer, and the second layer has a low lower permittivity than that of the first and third layers. ### Claim 8 (depends on 1) The antenna structure of claim 1, wherein the antenna structure has at least one band with a middle frequency that is below 2 gigahertz and a return loss that is less than −10 dB. ### Claim 9 (depends on 1) The antenna structure of claim 1, wherein the antenna structure has at least one band with a middle frequency that is below 1 gigahertz and a return loss that is less than −10 dB and a VSWR that is less than 2. ### Claim 10 (depends on 1) The antenna structure of claim 1, wherein the antenna structure has at least one band with a middle frequency that is below 2 gigahertz and an S11 that is less than −10 dB and a VSWR that is less than 2, and at least two bands each have a middle frequency that is above 2 gigahertz and a return loss that is less than −10 dB and a VSWR that is less than 2. ### Claim 11 (depends on 1) The antenna structure of claim 1, wherein the first and second antennas have the same geometric configuration. ### Claim 12 (depends on 1) The antenna structure of claim 1, further comprising a matching circuit that is connected to the first antenna feed point between a feed terminal, a ground terminal and the first antenna. ### Claim 13 (depends on 1) The antenna structure of claim 1, wherein the first and second antennas are printed dipoles or monopoles, wire dipoles or monopoles, omni-directional microstrip patches, small telescopic antennas or dielectric antennas. ### Claim 14 (depends on 1) The antenna structure of claim 1, wherein the second antenna and the resonator are in a common plane, which is parallel to a plane of the first antenna. ### Claim 15 (depends on 1) The antenna structure of claim 1, wherein the first and second antennas are separated by a plurality of dielectric layers, and wherein at least two of the dielectric layers have the same permittivity and another dielectric layer has permittivity that is lower than the at least two others. ### Claim 16 A multi-band antenna structure comprising: a first antenna having a matching circuit connected to feeding points of the first antenna; a second antenna spaced and electrically isolated from the first antenna and having a load connected to a feeding point of the second antenna; and an electrically floating split ring resonator spaced apart from the first and second antennas, wherein, the second antenna floats electrically, and wherein the antenna structure operates at a plurality of bandwidths and working band frequencies are selectable based on feeding point positions relative to a respective antenna length as well as impedance load values in both the first and second antennas. ### Claim 17 (depends on 16) The multi-band antenna of claim 16, further comprising at least first, second and third layers of dielectric material of a first, second and third thickness respectively disposed between the two antennas. ### Claim 18 (depends on 16) The multi-band antenna of claim 16, wherein a total thickness of the three layers of dielectric material is less than the quarter wavelength of a lowest middle frequency of the antenna structure. ### Claim 19 (depends on 18) The multi-band antenna of claim 18, wherein the first thickness of the first layer adjacent the first antenna is greater than the third thickness of the third layer adjacent the second antenna, and the first and third layers have the same permittivity. ### Claim 20 (depends on 16) The multi-band antenna of claim 16, wherein the first and second antennas are separated by a plurality of dielectric layers, and wherein at least two of the dielectric layers have the same permittivity and another dielectric layer has permittivity that is lower than the at least two others.