Multiband antenna assemblies including helical and linear radiating elements

摘要

Disclosed are exemplary embodiments of multiband antenna assemblies, which generally include helical and linear radiating elements. In an exemplary embodiment, a multiband antenna assembly may generally include at least one helical radiator having a longitudinal axis. At least one linear radiator is aligned with and/or disposed at least partially along the longitudinal axis of the at least one helical radiator. The antenna assembly is resonant in at least three frequency bands.

主权项

1. A multiband antenna assembly comprising:
at least one helical radiator having a longitudinal axis; and at least one linear radiator aligned with and/or disposed at least partially along the longitudinal axis of the at least one helical radiator; whereby the antenna assembly is resonant in at least three frequency bands; wherein:
the antenna assembly is resonant in an ultra high frequency (UHF) band from 380 MHz to 527 MHz, and a global positioning system (GPS) frequency band including a frequency of 1575 MHz; and the antenna assembly is also resonant in at least one of a very high frequency (VHF) band from 136 MHz to 174 MHz and/or a 7-800 MHz frequency band from 764 MHz to 870 MHz; andthe antenna assembly is omnidirectional for at least one or more frequency bands, including the ultra high frequency (UHF) band from 380 MHz to 527 MHz wherein the at least one linear radiator comprises first and second linear radiators coupled by first and second dielectric spacers such that the first and second linear radiators are not galvanically coupled to each other and such that the first and second linear radiators extend through one or more coils of the at least one helical radiator without galvanically coupling to the at least one helical radiator; wherein the at least one helical radiator includes:
a first dual pitch helical coil radiator having an upper portion and a lower portion, the lower portion having wider pitch coils than the upper portion; anda second dual pitch helical coil radiator having an upper portion and a lower portion, the lower portion having wider pitch coils than the upper portion; wherein:
the first dual pitch helical coil radiator corresponds to the VHF band and has an electrical length of about one quarter wavelength (λ/4) for the VHF band;the upper narrower pitch coils of the first dual pitch helical coil radiator are operable for helping to increase gain at lower frequency and for introducing another resonance at the VHF band;the upper narrow pitch coils of the second dual pitch helical coil radiator correspond to the UHF and 7-800 MHz with its second harmonic resonance frequency;the lower wider pitch coils of the second dual pitch helical coil radiator provide another resonance at 7-800 MHz and GPS band with its second harmonic resonance frequency;the second dual pitch helical coil radiator parasitically couples to the first linear radiator such that the combined electrical length of the first linear radiator and second dual pitch helical coil radiator is about three quarters wavelength (3λ/4) for the 7-800 MHz frequency band; andthe first linear radiator parasitically couples to the second linear radiator such that the first linear radiator has an electrical length of about one quarter wavelength (λ/4) for the UHF band.