Method of constructing multiple-frequency dipole or monopole antenna elements using closely-coupled resonators

A method of making a multiple-frequency antenna or antenna element that exhibits resonance at multiple arbitrary predetermined frequencies at a single feedpoint, comprising the steps of:

• providing a driven conductor operative on a first arbitrary predetermined frequency and including a feedpoint, said driven conductor comprising a one-quarter wavelength monopole;
• providing a non-driven conductor which is one-quarter wavelength resonant at a second arbitrary predetermined frequency different from said first frequency;
• and
• disposing said driven and non-driven conductors in a substantially parallel spaced relationship at a predetermined spacing to electromagnetically couple said driven and non-driven conductors and produce a non-reactive impedance at said feedpoint at both said first and second frequencies, wherein said predetermined spacing of said driven and non-driven conductors is determined according to the equation:
• ##EQU5## where, d.sub.12 is the spacing on centers between the driven and non-driven conductors, expressed in wavelengths at said second frequency;
• D is the diameter of the driven and non-driven conductors, expressed in wavelengths at said second frequency;
• Z.sub.0 is twice the desired impedance at said second frequency;
• F1 is the resonant frequency of said driven conductor;
• and
• F.sub.2 is the resonant frequency of said non-driven conductor.

A multiple-frequency antenna or antenna element that exhibits resonance at multiple arbitrary predetermined frequencies at a single feedpoint, comprising:

• a driven conductor operative on a first arbitrary predetermined frequency and including a feedpoint;
• a number n of non-driven conductors resonant at a number n of respective additional arbitrary predetermined frequencies different from said first frequency, wherein n is at least one;
• said driven and non-driven conductors disposed in substantially parallel spaced relationship at a predetermined spacing to electromagnetically couple said driven and non-driven conductors and produce a non-reactive impedance at said feedpoint at said first arbitrary predetermined frequency and at each of said n additional frequencies;
• and
• said predetermined spacing of said driven and non-driven conductors determined according to the equation:
• ##EQU6## where, d.sub.1n is the spacing on centers between the driven and non-driven conductors, expressed in wavelengths at said n additional frequency;
• D is the diameter of the driven and non-driven conductors, expressed in wavelengths at said n additional frequency;
• Z.sub.0 is the desired feedpoint impedance at said n additional frequency when the antenna element is a dipole, or twice the desired impedance when the antenna element is a monopole;
• F.sub.1 is the resonant frequency of the driven conductor;
• and
• F.sub.n is the resonant frequency of said n non-driven conductor.