# US 2008/0186243 A1 · VSWR improvement for bicone antennas > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0186243 A1 - Document ID: US20080186243A1 - Status: Published application - Kind: A1 - Application number: 12/012,879 - Filed: 2008-02-06 - Published: 2008-08-07 - Earliest claimed: 2007-02-06 - Assignees: EMS Technologies, Inc. - Inventors: Donald N. Black; John D. Voss; Terence D. Newbury - Web page: https://patentgrep.com/patent/US20080186243A1 ## 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: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract A broadband bicone antenna system supports improved VSWR operation of a high-impedance bicone antenna having a reduced aperture size, high input impedance at the central vertex of the cones, one or more pattern tuning filters associated with the cones, and input filtering for frequency selective impedance matching. Pattern tuning filters can improve the radiation pattern at different frequencies by controlling the electrical length of the antenna in response to the frequency components of the associated wideband signal. Impedance matching input filters can improve the signal matching to couple radio frequency energy into the antenna system from a feed line. Mutual tuning of the pattern tuning filters; the impedance matching input filters; and the impedance of the bicone antenna itself can improve the overall voltage standing wave ratio (VSWR) performance of the bicone antenna system over a broad range of operating frequencies. ## Claims ### Claim 1 An antenna system comprising: a first conductive element comprising a first substantially conical geometry; a second conductive element comprising a second substantially conical geometry and positioned on a common axis with the first conductive element to form a bicone antenna; a first filter in electrical communication with the first conductive element for frequency selective tuning of a radiation pattern of the antenna system; and a second filter in electrical communication with a central feed point of the bicone antenna for impedance matching into the antenna system, wherein the bicone antenna, the first filter, and the second filter are mutually tuned to achieve a reduction in a voltage standing wave ratio of the antenna system. ### Claim 2 (depends on 1) The antenna system of claim 1, wherein the first substantially conical geometry has a half angle of less than ten degrees, and the second substantially conical geometry has a half angle of less than ten degrees. ### Claim 3 (depends on 1) The antenna system of claim 1, wherein the bicone antenna has a characteristic impedance greater than 90 ohms. ### Claim 4 (depends on 1) The antenna system of claim 1, wherein an aperture size of the bicone antenna is less than one fifth of a lowest operating wavelength of the bicone antenna. ### Claim 5 (depends on 1) The antenna system of claim 1, wherein the first filter comprises a low-pass filter. ### Claim 6 (depends on 1) The antenna system of claim 1, wherein the first filter comprises an inductor. ### Claim 7 (depends on 1) The antenna system of claim 1, wherein the second filter comprises a tapered conductive strip. ### Claim 8 (depends on 1) The antenna system of claim 1, wherein the second filter comprises lumped filter components. ### Claim 9 (depends on 1) The antenna system of claim 1, wherein the second filter supports frequency selective impedance matching of complex impedances. ### Claim 10 An antenna system comprising: a first conductive cone element; a second conductive cone element positioned on a common axis with the first conductive cone element to form a bicone antenna comprising a first length of the bicone antenna along the common axis; and a filter in electrical communication with a central feed point of the bicone antenna for frequency selective impedance matching into the bicone antenna, wherein the bicone antenna, and the filter are mutually tuned to achieve a reduction in a voltage standing wave ratio of the antenna system. ### Claim 11 (depends on 10) The antenna system of claim 10, wherein the first conductive cone element has a half angle of less than ten degrees, and the second conductive cone element has a half angle of less than ten degrees. ### Claim 12 (depends on 10) The antenna system of claim 10, wherein the bicone antenna has a characteristic impedance greater than 90 ohms. ### Claim 13 (depends on 10) The antenna system of claim 10, wherein an aperture size of the bicone antenna is less than one fifth of a lowest operating wavelength of the bicone antenna. ### Claim 14 (depends on 10) The antenna system of claim 10, further comprising one or more filters disposed within the bicone antenna, along the first length of the bicone antenna, for turning a radiation pattern of the antenna system. ### Claim 15 (depends on 14) The antenna system of claim 14, wherein the one or more filters comprise inductive coils. ### Claim 16 (depends on 10) The antenna system of claim 10, wherein the filter comprises a tapered conductive strip. ### Claim 17 (depends on 10) The antenna system of claim 10, wherein the filter comprises lumped filter components. ### Claim 18 (depends on 10) The antenna system of claim 10, wherein the filter supports matching of complex impedances. ### Claim 19 A method for improved voltage standing wave ratio operation of a bicone antenna system comprising the steps of: providing a high-impedance bicone antenna, an impedance matching input filter in electrical communication with the high-impedance bicone antenna, and one or more pattern tuning filters positioned within one or both conductive cone elements of the bicone antenna; matching the impedance between the bicone antenna and a transmission line feeding the bicone antenna using the impedance matching input filter to provide frequency selective matching of complex impedances over a broad range of operating frequencies; controlling a radiation pattern of the bicone antenna using one or more frequency selective pattern tuning filters in response to bands of the operating frequencies; mutually tuning a characteristic impedance of the bicone antenna, a frequency selective response of the impedance matching input filter, and respective response characteristics of the one or more pattern matching filters to substantially reduce the voltage standing wave ratio of the bicone antenna system; and exciting the bicone antenna to induce the propagation of electromagnetic waves in a medium surrounding the antenna. ### Claim 20 (depends on 19) The method of claim 19, wherein the step of controlling a radiation pattern of the bicone antenna comprises providing frequency selective control of an electrical length of the bicone antenna. ### Claim 21 An antenna system comprising: a conductive cone antenna element comprising a base, a vertex, and an input port leading to the vertex; and a filter electrically connected to the input port for frequency selective impedance matching into the conductive cone antenna element, wherein the conductive cone antenna element and the filter are collectively tuned for managing voltage standing wave ratio of the antenna system. ### Claim 22 (depends on 21) The antenna system of claim 21, wherein the filter and the conductive cone antenna element are further tuned for reducing voltage standing wave ratio of the antenna system. ### Claim 23 (depends on 21) The antenna system of claim 21, wherein the filter and the conductive cone antenna provide the antenna system a first voltage standing wave ratio that is substantially lower than a second voltage standing wave ratio of the conductive cone operated without the filter.