Non-grounded type ultrahigh frequency antenna
Patent 4929961 Issued on May 29, 1990. Estimated Expiration Date: 
April 24, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
April 24, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesDecoupling means for monopole antennas and the like Combination microstrip and unipole antenna Vertical antenna with improved artificial ground system Patent #: 4658266 InventorAssigneeApplicationNo. 342181 filed on 04/24/1989US Classes:343/715, Rod type343/829, With grounding structure, including counterpoises343/846With grounding structure (including counterpoises)ExaminersPrimary: Hille, RolfAssistant: Johnson, Doris J. Attorney, Agent or FirmInternational ClassesH01Q 001/32H01Q 009/38 AbstractA non-grounded type ultrahigh frequency antenna including an antenna element having a length of λ/2 at a working frequency, a casing provided at the base of the antenna element, a metal section of the casing having a length of approximately λ/4 at the working frequency, and a metal plate provided in the casing and parallel to the metal section, one end of the metal plate being connected to the metal section and other end to the antenna element. The antanna is made parallel-resonant within a working frequency band by an electrostatic capacitance created between the metal plate and metal section and an inductance of the metal plate. The antenna element can be made slightly shorter than a length λ/2 at the working frequency and another metal plate can be provided between the antenna element and the metal plate so that a constant K-filter is formed by an electrostatic capacitance created by the another metal plate and the metal plate and a residual inductance of the antenna element.Field of SearchSupported by vehicle bodyRod type With grounding structure (including counterpoises) Rod type Artificial or substitute grounds (e.g., ground planes) Insulated from or capacity coupled to ground With vehicle Vehicle part of active antenna or vice versa With grounding structure, including counterpoises With coaxial feed line | |
