Low profile, broad band monopole antenna

• US 4,890,116 A
• Filed: 04/09/1986
• Issued: 12/26/1989
• Est. Priority Date: 04/09/1986
• Status: Expired due to Fees

• Current Assignee: Shakespeare Company LLC (Newell Brands Inc.)
• Original Assignee: Shakespeare Company LLC (Newell Brands Inc.)
• Inventors: Lewis, John R. Jr.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Wise, Robert E.
• Application Number:
  US06/849,884
• Time in Patent Office: 1,357 Days
• Field of Search: 343/749, 343/860, 343/862, 343/865, 343/722, 343/750, 343/752, 343/850
• US Class Current: 343/749
• CPC Class Codes: H01Q 9/32 Vertical arrangement of element H01Q9/40 takes precedence

Abstract

A low-profile, broad band monople antenna (10) includes two linear radiators (11,13), a resistor network (18), and a transmission line network (20), all connected in series in that order. Linear radiator (11) includes a capacitor (12) which reduces the apparent electrical length of the antenna and provides high voltage isolation. Resistor network (18) reduces VSWR at lower frequencies in the band of interest such that in combination with the other elements, the VSWR for antenna (10) is sufficiently low that no further matching or tuning is necessary over the entire broad frequency band of interest without significant loss of gain relative to that of a monopole antenna one-quarter wave resonant at each frequency throughout the frequency band of interest.

Claims

1. A low-profile, monopole antenna operable over a predetermined broad band and connected to a transmission line, comprising

a radiator including means for providing a series capacitance, and radiator including first linear radiator and second linear radiator operatively connected to one end of said first linear radiator.

network means for substantially coupling and matching the impedance of the antenna with the impedance of the transmission line to which it is connected, said network means operatively connected to said radiator;

and,

resistance means for minimizing the antenna'"'"'s voltage standing wave ration (VSWR) over lower frequencies in said broad band to make tuning unnecessary and gain approximate that of a one-quarter wavelength monopole over substantially all frequencies in said broad band, said resistance means electrically connected in series between said network means and the end of said linear radiator opposite that connected to said first linear radiator, and the resistance of said resistance means reducing VSWR at the lower frequencies in the range of approximately 30 MHz to 90 Mhz.

2. A low-profile, monopole antenna operable over a predetermined broad band and connected to a transmission line, comprising:

a radiator including means for providing a series capacitance, said radiator including first linear radiator and second linear radiator operatively connected to one end of said first linear radiator, said means for providing a series capacitance including conductive member means electrically connected to a first portion of said first linear radiator for extension into a second portion of said first linear radiator, and dielectric spacer means secured within said second portion of said first linear radiator within which said conductive member means is extended to provide said series capacitance;

network means for substantially coupling and matching the impedance of the antenna with the impedance of the transmission line to which it is connected, said network means operatively connected to said radiator; and

,

resistance means for minimizing the antenna,s voltage standing wave ratio (VSWR) over lower frequencies in said broad band to make tuning unnecessary and gain approximate that of a one-quarter wavelength monopole over substantially all frequencies in said broad band, said resistance means electrically connected in series between said network means and the end of said second linear radiator opposite that connected to said first linear radiator.

3. A low-profile, monopole antenna operable over a predetermined broad band and connected to a transmission line, comprising

a radiator including means for providing a series capacitance, said radiator including first linear radiator and second linear radiator operatively connected to one end of said first linear radiator;

network means for substantially coupling and matching the impedance of the antenna with the impedance of the transmission line to which it is connected, said network means operatively connected to said radiator, said network means including broad band transformer means for coupling the antenna to the transmission line and means for matching the impedance of the antenna with the impedance of the transmission line over said broad band of interest; and

,

resistance means for minimizing the antenna,s voltage standing wave ratio (VSWR) over lower frequencies in said broad band to make tuning unnecessary and gain approximate that of a one-quarter wavelength monopole over substantially all frequencies in said broad band, said resistance means electrically connected in series between said network means and the end of said second linear radiator opposite that connected to said first linear radiator.

4. A low-profile, monopole antenna, as set forth in claim 3, wherein said broad band transformer means includes a toroidal impedance matching transformer.

5. A low-profile, monopole antenna, as set forth in claim 3, wherein said means for matching the impedance of the antenna with the impedance of the transmission line includes a transmission line and a matching capacitor.