# US 9,437,917 B2 · Antenna designs > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,917 B2 - Document ID: US9437917B2 - Status: Granted - Kind: B2 - Application number: 14/471,497 - Filed: 2014-08-28 - Published: 2016-03-03 - Granted: 2016-09-06 - Earliest claimed: 2014-08-28 - Assignees: Aruba Networks, Inc. - Applicants: Aruba Networks, Inc. - Inventors: Ahmed Khidre; James W. Jervis; Subburajan Ponnuswamy - Web page: https://patentgrep.com/patent/US9437917B2 ## CPC - H01Q 1/007: {specially adapted for indoor communication} - H01Q 9/0421: {with a shorting wall or a shorting pin at one end of the element (H01Q9/0414 takes precedence)} - H01Q 9/42: with folded element, the folded parts being spaced apart a small fraction of the operating wavelength - H01Q 21/24: Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction {(circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001)} - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract According to one embodiment of the invention, a network device comprises a plurality of antennas comprising a first antenna, wherein the first antenna comprises: a first set of one or more elements that form an Alford loop and that is configured for electrical excitation via a current transmitted over a conductive medium from a signal source and a second set of one or more elements that is configured for electromagnetic induction without contact with the conductive medium from the signal source. ## Claims ### Claim 1 A device comprising: a semi-loop antenna consisting essentially of: a first section connected to a ground plane via a connection portion and extending away from the ground plane, a second section connected to an end of the first section, the second section being planar and facing the ground plane, and a third section connected to an end of the second section and extending toward the ground plane without coming into direct contact with the ground plane, wherein the third section is connected to a signal source via a connector, and an area of the second section and a distance of the second section from the ground plane are such that an inductance corresponding to the semi-loop antenna is canceled by a capacitance corresponding to the semi-loop antenna. ### Claim 2 (depends on 1) The device of claim 1, wherein the area of the second section and the distance of the second section from the ground plane are such that an impedance corresponding to the semi-loop antenna is 50 Ohms. ### Claim 3 (depends on 1) The device of claim 1, wherein the area of the second section and the distance of the second section from the ground plane are such that an impedance corresponding to the semi-loop antenna is 25 Ohms. ### Claim 4 (depends on 1) The device of claim 1, wherein the area of the second section and the distance of the second section from the ground plane are such that an impedance corresponding to the semi-loop antenna is 75 Ohms. ### Claim 5 (depends on 1) The device of claim 1, wherein the area of the second section is two or more times each of an area of the first section and an area of the third section. ### Claim 6 (depends on 1) The device of claim 1, further comprising: a plurality of semi-loop antennas, including the semi-loop antenna, each consisting essentially of: a first section connected to the ground plane via a connection portion and extending away from the ground plane, a second section connected to an end of the first section, the second section being planar and facing the ground plane, and a third section connected to an end of the second section and extending toward the ground plane without coming into direct contact with the ground plane; and a plurality of monopole antennas, wherein, for each of the plurality of semi-loop antennas: the third section is connected to a signal source via a connector, and an area of the second section and a distance of the second section from the ground plane are such that an inductance corresponding to the respective semi-loop antenna is canceled by a capacitance corresponding to the respective semi-loop antenna, and the plurality of semi-loop antennas and the plurality of the monopole antennas are arranged in an alternating pattern on the ground plane. ### Claim 7 (depends on 6) The device of claim 6, wherein each of the plurality of monopole antennas is closer to a center of the ground plane than each of the plurality of semi-loop antennas. ### Claim 8 A device comprising: a monopole antenna consisting essentially of: a first section connected to a ground plane via a connection portion and extending away from the ground plane, a second section connected to an end of the first section, the second section being planar and facing the ground plane, and a third section connected to an end of the second section and extending away from the ground plane, wherein the third section is connected to a signal source via a connector without the third section coming into direct contact with the ground plane, and a height of the first section, a length of the second section, and dimensions of the third section are such that a capacitance corresponding to the monopole antenna is canceled by an inductance corresponding to the monopole antenna. ### Claim 9 (depends on 8) The device of claim 8, wherein the height of the first section, the length of the second section, and the dimensions of the third section are such that an impedance corresponding to the monopole antenna is 50 Ohms. ### Claim 10 (depends on 8) The device of claim 8, wherein the height of the first section, the length of the second section, and the dimensions of the third section are such that an impedance corresponding to the monopole antenna is 25 Ohms. ### Claim 11 (depends on 8) The device of claim 8, wherein the height of the first section, the length of the second section, and the dimensions of the third section are such that an impedance corresponding to the monopole antenna is 75 Ohms. ### Claim 12 (depends on 8) The device of claim 8, wherein a highest point of the third section relative to the ground plane is no more than 15 millimeters from the ground plane. ### Claim 13 (depends on 8) The device of claim 8, wherein a length of the third section is less than or equal to 11 millimeters. ### Claim 14 (depends on 8) The device of claim 8, further comprising: a plurality of monopole antennas, including the monopole antenna, each consisting essentially of: a first section connected to a ground plane via a connection portion and extending away from the ground plane, a second section connected to an end of the first section, the second section being planar and facing the ground plane, and a third section connected to an end of the second section and extending away from the ground plane; and a plurality of semi-loop antennas, wherein, for each of the plurality of monopole antennas: the third section is connected to a signal source via a connector, and a height of the first section, a length of the second section, and dimensions of the third section are such that a capacitance corresponding to the monopole antenna is canceled by an inductance corresponding to the monopole antenna, and the plurality of semi-loop antennas and the plurality of the monopole antennas are arranged in an alternating pattern on the ground plane. ### Claim 15 (depends on 14) The device of claim 14, wherein each of the plurality of monopole antennas is closer to a center of the ground plane than each of the plurality of semi-loop antennas.