# US 2008/0186244 A1 · Frequency control of electrical length 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 2008/0186244 A1 - Document ID: US20080186244A1 - Status: Published application - Kind: A1 - Application number: 12/012,880 - 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; Michael G. Guler - Web page: https://patentgrep.com/patent/US20080186244A1 ## 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 supports frequency selective control of electrical length. Frequency selective control of the electrical length of an antenna can provide an antenna exhibiting two or more different electrical lengths where use of each length depends upon the operating frequencies of the signals. The electrical length of the bicone antenna may be reduced in response to higher operating frequencies. Such reduction in electrical length at higher frequencies can provide improved antenna radiation patterns for the antenna. Further, the electrical length of the bicone antenna may be increased in response to low frequency operation. Such increase in electrical length may improve VSWR performance at lower frequencies. Simultaneous operation of the bicone antenna at varied electrical lengths for varied frequency bands can provide improved broadband performance of the antenna. ## 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 first bicone antenna comprising a first length along the common axis; a filter element disposed at a distal end of the first conductive element and in electrical communication with the first conductive element; and a third conductive element comprising a truncated-cone geometry and positioned on the common axis distal to the filter element and in electrical communication with the filter element, wherein the first conductive element, the second conductive element, the filter element, and the third conductive element form a second bicone antenna comprising a second length along the common axis. ### Claim 2 (depends on 1) The antenna system of claim 1, wherein the filter element is operable to substantially restrict a high frequency signal to the first bicone antenna and operable to substantially conduct a low frequency signal to the second bicone antenna. ### Claim 3 (depends on 1) The antenna system of claim 1, wherein a transition frequency of the filter element is operable to restrict a frequency range of signals to the first bicone antenna in response to the frequency range being substantially tuned to the first length. ### Claim 4 (depends on 1) The antenna system of claim 1, wherein a transition frequency of the filter element is operable to substantially conduct a frequency range of signals to the second bicone antenna in response to the frequency range being substantially tuned to the second length. ### Claim 5 (depends on 1) The antenna system of claim 1, wherein the filter element comprises a low-pass filter. ### Claim 6 (depends on 1) The antenna system of claim 1, wherein the filter element comprises an inductor. ### Claim 7 (depends on 1) The antenna system of claim 1, wherein the filter element comprises a coil. ### Claim 8 (depends on 1) The antenna system of claim 1, wherein the filter element comprises a conductive helix mechanically coupled within a partition of the first conductive element. ### Claim 9 (depends on 1) The antenna system of claim 1, wherein the filter element comprises a conductive helix, and a surface of the first conductive element is threaded to mate with an interior surface of the conductive helix. ### Claim 10 (depends on 1) The antenna system of claim 1, further comprising a secondary filter element disposed distal to the third conductive element, and a fourth conductive element positioned distal to the secondary filter element along the common axis; wherein the first conductive element, the second conductive element, the third conductive element, the fourth conductive element, the filter element, and the secondary filter element form a third bicone antenna comprising a third length along the common axis. ### Claim 11 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 along the common axis; and one or more filter elements disposed along the first length and subdividing the bicone antenna into one or more reduced length bicone antennas having electrical lengths less than the first length. ### Claim 12 (depends on 11) The antenna system of claim 11, wherein one or more filter elements are operable to restrict ranges of frequencies to respective reduced length bicone antennas in response to the reduced length bicone antennas comprising respective lengths tuned to the respective ranges of frequencies. ### Claim 13 (depends on 11) The antenna system of claim 11, wherein each of the one or more filter elements comprises a low-pass filter. ### Claim 14 (depends on 11) The antenna system of claim 11, wherein each of the one or more filter elements comprises an inductor. ### Claim 15 (depends on 11) The antenna system of claim 11, wherein each of the one or more filter elements comprises a coil. ### Claim 16 (depends on 11) The antenna system of claim 11, wherein each of the one or more filter elements comprises a conductive helical element. ### Claim 17 A method for operating a bicone antenna with frequency controlled electrical length comprising the steps of: providing the bicone antenna with a filter element positioned within conductive cone elements of the bicone antenna; restricting a high frequency range of a wideband signal to a reduced length of the bicone antenna in response to the filter element providing a substantially open circuit at high frequencies; exciting the reduced length of the bicone antenna with the high frequency range of the wideband signal to induce propagation of electromagnetic waves in a medium surrounding the antenna; permitting a low frequency range of the wideband signal to excite an increased length of the bicone antenna in response to the filter element providing a substantially closed circuit at lower frequencies; and exciting the increased length of the bicone antenna with the low frequency range of the wideband signal to induce propagation of electromagnetic waves in a medium surrounding the antenna. ### Claim 18 (depends on 17) The method of claim 17, further comprising the step of coupling the wideband signal from a transmission line into the bicone antenna. ### Claim 19 (depends on 17) The method of claim 17, further comprising the step of providing multiple filter elements to mechanically subdivide the bicone antenna into multiple reduced lengths while electrically isolating multiple frequency ranges to respective reduced lengths. ### Claim 20 (depends on 17) The method of claim 17, further comprising the step of dynamically selecting an electrical length for operating the bicone antenna in response to a frequency range of the wideband signal and a frequency response of the filter element. ### Claim 21 An antenna system comprising: a conductive cone element comprising: a first section having a conical form; and a second section having a truncated conical form; and a filter element disposed between the first section and the second section. ### Claim 22 (depends on 21) The antenna system of claim 21, wherein the first section comprises a base and a point, wherein the second section comprises a first end and a second end, wherein the truncated conical form tapers down from the first end to the second end, and wherein the filter element is adjacent the base and the second end. ### Claim 23 (depends on 22) The antenna system of claim 22, wherein the filter element comprises a conductive helix in electrical contact with the base and the second end.