Dual-band interspersed cellular basestation antennas

Abstract

Low-band radiators of an ultra-wideband dual-band dual-polarization cellular basestation antenna and ultra-wideband dual-band dual-polarization cellular base-station antennas are provided. The dual bands comprise low and high bands. The low-band radiator comprises a dipole comprising two dipole arms adapted for the low band and for connection to an antenna feed. At least one dipole arm of the dipole comprises at least two dipole segments and at least one radiofrequency choke. The choke is disposed between the dipole segments. Each choke provides an open circuit or a high impedance separating adjacent dipole segments to minimize induced high band currents in the low-band radiator and consequent disturbance to the high band pattern. The choke is resonant at or near the frequencies of the high band.

The invention claimed is: 
     
       1. A base station antenna, comprising:
 a low-band radiating element that is configured to radiate in a low frequency band, the low-band radiating element including a first dipole antenna comprising a first dipole arm and a second dipole arm that are connected to a first antenna feed, the low-band radiating element comprising a second dipole antenna comprising a third dipole arm and a fourth dipole arm that are configured in a cross configuration with the first dipole arm and the second dipole arm of the first dipole antenna; and 
 a plurality of high-band radiating elements that are configured to radiate in a high frequency band that is higher than the low frequency band, 
 wherein the first dipole arm includes a first dipole segment and a second dipole segment that are separated by a resonating element that resonates in or near the high frequency band, and 
 wherein the third dipole arm and the fourth dipole arm are each resonant at approximately a quarter wavelength (λ/4). 
 
     
     
       2. The base station antenna of  claim 1 , wherein the resonating element comprises a radio frequency (RF) choke. 
     
     
       3. The base station antenna of  claim 1 , wherein the low-band radiating element comprises a conductor that includes gaps that behave as an open circuit to reduce the effect of radiation emitted by the low-band radiating element on the radiation emitted by the high-band radiating elements. 
     
     
       4. The base station antenna of  claim 1 , wherein the low-band radiating element comprises a conductor that includes gaps that behave as a high impedance to reduce the effect of radiation emitted by the low-band radiating element on the radiation emitted by the high-band radiating elements. 
     
     
       5. The base station antenna of  claim 1 ,
 wherein the first dipole segment comprises an electrically conducting elongated body, and 
 wherein the elongated body is open circuited at one end and short circuited at another end to a center conductor. 
 
     
     
       6. The base station antenna of  claim 5 , wherein the electrically conducting elongated body is cylindrical or tubular in form. 
     
     
       7. The base station antenna of  claim 5 , wherein the center conductor connects to the another end that is short circuited to the center conductor. 
     
     
       8. The base station antenna of  claim 1 , wherein the resonating element comprises a coaxial choke. 
     
     
       9. The base station antenna of  claim 6 , wherein the electrically conducting elongated body is cylindrical. 
     
     
       10. The base station antenna of  claim 9 , wherein the space between the electrically conducting elongated body that is cylindrical and the center conductor is partially filled with air. 
     
     
       11. The base station antenna of  claim 9 ,
 wherein the space between the electrically conducting elongated body that is cylindrical and the center conductor is filled or partly filled with dielectric material. 
 
     
     
       12. The base station antenna of  claim 1 ,
 wherein the low-band radiating element operates in a frequency range of 698-960 MHz. 
 
     
     
       13. The base station antenna of  claim 1 , wherein the low-band radiating element comprises a first dipole antenna, and wherein the base station antenna further comprises:
 a second dipole antenna comprising a third dipole arm and a fourth dipole arm that are configured in a cross configuration with the first dipole arm and the second dipole arm of the first dipole antenna,   wherein the third dipole arm and the fourth dipole arm are each resonant at approximately a quarter wavelength (λ/4).   
     
     
       14. A multi-band base station antenna including a first radiating element comprising a first dipole radiating element operating in a first frequency band and a second radiating element operating in a second frequency band, the first dipole radiating element comprising:
 a first dipole arm; 
 a second dipole arm; and 
 a feed line coupled to the first and second dipole arms, 
 wherein the first and second dipole arms each further comprise an inner conductor and a plurality of discontinuous outer conductors, the plurality of discontinuous outer conductors being open circuited at a first end and short circuited at a second end, and 
 wherein a discontinuity in the plurality of discontinuous outer conductors comprises a radio frequency (RF) choke that is dimensioned to be resonant at or near the second frequency band. 
 
     
     
       15. The multi-band base station antenna of  claim 14 , wherein the
 wherein an outer conductor of the plurality of discontinuous outer conductors comprises an electrically conducting elongated body, and 
 wherein the elongated body is open circuited at one end and short circuited at another end to the inner conductor. 
 
     
     
       16. A low-band radiator of an ultra-wideband dual-band dual-polarization cellular basestation antenna, the bands comprising low and high bands, the low-band radiator comprising:
 a dipole antenna comprising a first dipole arm and a second dipole arm adapted for the low band and for connection to an antenna feed, 
 wherein the first dipole arm comprises a first dipole segment and a second dipole segment separated by a coaxial choke disposed between the first dipole segment and the second dipole segment, and 
 wherein the coaxial choke is resonant at or near the frequencies of the high band thereby reducing induced high band currents in the low-band radiator and consequent disturbance to the high band. 
 
     
     
       17. The low-band radiator of  claim 16 ,
 wherein the coaxial choke comprises a center conductor and a gap in an outer conductor of the coaxial choke protruding from a portion of the center conductor that extends between the first dipole segment and the second dipole segment, and 
 wherein the coaxial choke has a length of a quarter wavelength (λ/4) or less at frequencies in the bandwidth of the high band. 
 
     
     
       18. The low-band radiator of  claim 16 , wherein the RF choke provides an open circuit between the first dipole segment and the second dipole segment. 
     
     
       19. The low-band radiator of  claim 16 , wherein the RF choke provides a high impedance between the first dipole segment and the second dipole segment. 
     
     
       20. The low-band radiator of  claim 16 , wherein the center conductor has a thickness adapted to provide immunity from disturbance of the high-band radiation pattern by the low-band radiator over the entire high-band bandwidth. 
     
     
       21. The low-band radiator of  claim 16 , further comprising: in combination with parasitic dipole elements that are substantially parallel to the first dipole arm and/or the second dipole arm, and are configured to adjust phase of a current in the first dipole arm and/or the second dipole arm. 
     
     
       22. A base station antenna, comprising:
 a lower frequency band radiator;   a higher frequency band radiator;   a first parasitic element that includes a first metal dipole arm, a second metal dipole arm and a first inductive element coupled between the first metal dipole arm and the second metal dipole arm; and   a second parasitic element that includes a third metal dipole arm, a fourth metal dipole arm and a second inductive element coupled between the third metal dipole arm and the fourth metal dipole arm,   wherein the first and second parasitic elements together with a first dipole of the lower frequency band radiator are configured to narrow a horizontal beamwidth of an antenna beam generated by the lower frequency band radiator.   
     
     
       23. The base station antenna of  claim 22 , wherein the higher frequency band radiator is part of a vertically-extending array of higher frequency band radiators, wherein the first and second parasitic elements are on opposite sides of the lower frequency band radiator, and wherein the lower frequency band radiator is positioned along a horizontal axis that connects the first and second parasitic elements. 
     
     
       24. A base station antenna, comprising:
 a lower frequency band radiator;   a higher frequency band radiator;   a first parasitic element that includes a first metal dipole arm, a second metal dipole arm and a first inductive element coupled between the first metal dipole arm and the second metal dipole arm; and   a second parasitic element that includes a third metal dipole arm, a fourth metal dipole arm and a second inductive element coupled between the third metal dipole arm and the fourth metal dipole arm,   wherein the lower frequency band radiator comprises a first lower frequency band radiator of an array of lower frequency band radiators, and wherein the first lower frequency band radiator is positioned between the first parasitic element and the second parasitic element.   
     
     
       25. The base station antenna of  claim 24 , wherein the higher frequency band radiator comprises a first higher frequency band radiator of an array of higher frequency band radiators, wherein the array of higher frequency band radiators is positioned in between the first parasitic element and the array of lower frequency band radiators. 
     
     
       26. The base station antenna of  claim 25 , wherein the array of lower frequency band radiators is a vertically-extending array of lower frequency band radiators, wherein the array of higher frequency band radiators is a vertically-extending array of higher frequency band radiators, and wherein the first lower frequency band radiator is positioned along a horizontal axis that extends between the first parasitic element and the second parasitic element. 
     
     
       27. A base station antenna, comprising:
 a lower frequency band radiator;   a higher frequency band radiator; and   a first parasitic element that includes a first metal dipole arm, a second metal dipole arm and a first inductive element coupled between the first metal dipole arm and the second metal dipole arm,   wherein the lower frequency band radiator is part of a vertically-extending array of lower frequency band radiators, wherein the higher frequency band radiator is part of a vertically-extending array of higher frequency band radiators, and wherein the first parasitic element is part of a first vertically-extending array of parasitic elements.   
     
     
       28. The base station antenna of  claim 27 , wherein the vertically-extending array of higher frequency band radiators is positioned between the vertically-extending array of higher frequency band radiators and the first vertically-extending array of parasitic elements. 
     
     
       29. The base station antenna of  claim 28 , further comprising a second vertically-extending array of parasitic elements, wherein the vertically-extending array of lower frequency band radiators is positioned between the first and second vertically-extending arrays of parasitic elements. 
     
     
       30. A base station antenna, comprising:
 a lower frequency band radiator;   a higher frequency band radiator; and   a first parasitic element that includes a first metal dipole arm, a second metal dipole arm and a first inductive element coupled between the first metal dipole arm and the second metal dipole arm,   wherein the first and second metal dipole arms comprise metallization on a printed circuit board.   
     
     
       31. The base station antenna of  claim 30 , wherein the first inductive element is configured to adjust the phase of currents in the first and second dipole arms. 
     
     
       32. The base station antenna of  claim 31 , wherein the first inductive element is configured to adjust the phase of currents in the first and second dipole arms to bring the currents in the first and second dipole arms into an improved relationship to a current in a dipole of the lower frequency radiator. 
     
     
       33. A base station antenna, comprising:
 a lower frequency band radiator;   a higher frequency band radiator; and   a first parasitic element that includes a first metal dipole arm, a second metal dipole arm and a first inductive element coupled between the first metal dipole arm and the second metal dipole arm,   wherein the first lower frequency band radiator comprises a first dipole that includes a first dipole arm and a second dipole arm,   wherein the first dipole arm includes at least a first segment and a second segment that are separated by a gap,   wherein the first segment is electrically connected to the second segment, and   wherein an electrical element is disposed between the first segment and the second segment of the first dipole arm, the electrical element configured to reduce high band currents in the first lower frequency band radiator.   
     
     
       34. The base station antenna of  claim 33 , wherein the first and second segments of the first dipole arm are separated by a high impedance section. 
     
     
       35. The base station antenna of  claim 33 , wherein the first segment and the second segment of the first dipole arm each comprise an electrically conducting elongated body. 
     
     
       36. The base station antenna of  claim 33 , wherein the gap is configured to interrupt currents in the higher frequency band. 
     
     
       37. The base station antenna of  claim 33 , wherein the first dipole is coupled to an antenna feed of the base station antenna by a series inductor. 
     
     
       38. A base station antenna, comprising:
 a lower frequency band radiator;   a higher frequency band radiator; and   a first parasitic element that includes a first metal dipole arm, a second metal dipole arm and a first inductive element coupled between the first metal dipole arm and the second metal dipole arm,   wherein the first lower frequency band radiator comprises a first dipole that includes a first dipole arm and a second dipole arm,   wherein the first dipole arm includes at least a first segment and a second segment that are separated by a gap,   wherein the first lower frequency band radiator comprises a second dipole, and   wherein the first and second dipoles are in a cross configuration.   
     
     
       39. A base station antenna, comprising:
 a lower frequency band radiator;   a higher frequency band radiator; and   a first parasitic element that includes a first metal dipole arm, a second metal dipole arm and a first inductive element coupled between the first metal dipole arm and the second metal dipole arm,   wherein the higher frequency band radiator comprises an ultrawideband radiator that operates in the 1710-2690 MHZ frequency range.   
     
     
       40. A base station antenna, comprising:
 a lower frequency band radiator;   a higher frequency band radiator; and   a first parasitic element that includes a first metal dipole arm, a second metal dipole arm and a first inductive element coupled between the first metal dipole arm and the second metal dipole arm,   wherein the lower frequency band radiator comprises first and second crossed dipoles that are positioned at a height of about one-quarter of a wavelength of a frequency within the lower frequency band above a metal groundplane.   
     
     
       41. A base station antenna, comprising:
 a lower frequency band radiator;   a higher frequency band radiator; and   a first parasitic element that includes a first metal dipole arm, a second metal dipole arm and a first inductive element coupled between the first metal dipole arm and the second metal dipole arm,   wherein the first metal dipole arm and the second metal dipole arm are each approximately one quarter of a wavelength of a frequency within the lower frequency band.   
     
     
       42. An auxiliary radiating element for a base station antenna, comprising:
 a first metal dipole arm;   a second metal dipole arm; and   an inductive element coupled between the first metal dipole arm and the second metal dipole arm,   wherein the auxiliary radiating element is a non-driven parasitic element,   wherein the first and second metal dipole arms comprise metallization on a printed circuit board, and   wherein the inductive element is configured to adjust the phase of currents in the first and second metal dipole arms to bring the currents into an improved relationship to a current in a dipole of a radiating element of the base station antenna.