Patent ID: 7262738

Claim:
A combination antenna having multi-mode and multi-band arrangements, comprising: a conductive seat; a non-uniform helical antenna extending from one end of the conductive seat, the helical antenna comprising a first coil section and a second coil section, wherein the first coil section has a spiral angle less than a spiral angle of the second coil section, a pitch less than a pitch of the second coil section, and coils arranged in a more dense arrangement as compared to that of the second coil section such that the first coil section is adapted to be tuned to a plurality of resonant frequencies different from that to which the second coil section is adapted to be tuned; and a pole antenna extending from one end of the conductive seat through the helical antenna, a plurality of physical parameters of the pole antenna capable of being adjusted for tuning the pole antenna to a plurality of resonant frequencies different from that to which the helical antenna is tuned, wherein the characteristic of the helical antenna depends on a ratio (D/λ) of coil diameter D to wavelength λ, the ratio D/λ is less than 1.8, and electric field and direction coefficients of the helical antenna are represented as: l 2 = S 2 + ( π ⁢ ⁢ D ) 2 = ( S Sin ⁢ ⁢ θ ) 2 h = NS } ⁢ ⁢ E φ = 120 ⁢ π 2 ⁢ I r ⁢ A λ 2 ⁢ Sin ⁢ ⁢ θ E θ = j ⁢ 60 ⁢ π ⁢ ⁢ I r ⁢ S λ ⁢ Sin ⁢ ⁢ θ where D is average coil diameter, S is pitch, h is axial length, l is average length of coil, θ is spiral angle, and N is the number of turns.