This application describes multi-band antenna systems and base stations. An example multi-band antenna system includes: a plurality of radiating element arrays, feeding networks separately corresponding to the plurality of radiating element arrays, at least one layer of a frequency selective surface (FSS), and a reflection panel. The plurality of radiating element arrays are located above the reflection panel. All or some of the plurality of radiating element arrays are stacked. The at least one layer of the FSS is located between the stacked radiating element arrays. A feeding network corresponding to at least one radiating element array in the stacked radiating element arrays is electrically connected to the at least one layer of the FSS, or the feeding network corresponding to the at least one radiating element array is integrated on the at least one layer of the FSS.

An antenna assembly has a conductive line coupled to a feed point. An element is configured to resonate at a predetermined frequency. The element is electrically coupled to the conductive line and aligned perpendicular to the conductive line wherein the predetermined frequency of the element determines a distance from the feed point along the conductive line.

An antenna assembly has a conductive line coupled to a feed point. An element is configured to resonate at a predetermined frequency. The element is electrically coupled to the conductive line and aligned perpendicular to the conductive line wherein the predetermined frequency of the element determines a distance from the feed point along the conductive line.

A rear glass according to the invention is for attachment to a lift-up backdoor that closes an opening in a rear portion of a vehicle, and includes a glass plate, a defogger disposed in a vicinity of a center of the glass plate in an up-down direction, and a shared antenna installed on the glass plate upward or downward of the defogger, the shared antenna including a power supply unit, an AM antenna connected to the power supply unit, and an FM antenna connected to the power supply unit, and a relationship between an element length L.sub.AM of the AM antenna, a center wavelength λ.sub.FM-C corresponding to a reception frequency band of the FM antenna and a wavelength shortening coefficient α of the glass plate satisfying 0.49×α×λ.sub.FM-C≤L.sub.AM≤0.67×α×λ.sub.FM-C.

A rear glass according to the invention is for attachment to a lift-up backdoor that closes an opening in a rear portion of a vehicle, and includes a glass plate, a defogger disposed in a vicinity of a center of the glass plate in an up-down direction, and a shared antenna installed on the glass plate upward or downward of the defogger, the shared antenna including a power supply unit, an AM antenna connected to the power supply unit, and an FM antenna connected to the power supply unit, and a relationship between an element length L.sub.AM of the AM antenna, a center wavelength λ.sub.FM-C corresponding to a reception frequency band of the FM antenna and a wavelength shortening coefficient α of the glass plate satisfying 0.49×α×λ.sub.FM-C≤L.sub.AM≤0.67×α×λ.sub.FM-C.

An antenna array is provided which may include different levels of antenna elements on the array. A first set of antenna elements are arranged on a first set of reflectors with the reflectors being arranged in a shape having corners. A second set of reflectors with a second set of antenna elements are mounted on the corners of the first set of reflectors. A third set of reflectors is arranged in another shape with a third set of antenna elements being on the faces of the third set of reflectors. The first and second set of reflectors and antenna elements are on a first level of the array and the third set of reflectors and antenna elements are on a second level of the array. The third set of reflectors and antenna elements are between the first level and the base plate of the array.

An antenna array is provided which may include different levels of antenna elements on the array. A first set of antenna elements are arranged on a first set of reflectors with the reflectors being arranged in a shape having corners. A second set of reflectors with a second set of antenna elements are mounted on the corners of the first set of reflectors. A third set of reflectors is arranged in another shape with a third set of antenna elements being on the faces of the third set of reflectors. The first and second set of reflectors and antenna elements are on a first level of the array and the third set of reflectors and antenna elements are on a second level of the array. The third set of reflectors and antenna elements are between the first level and the base plate of the array.

A base station antenna includes a column of radiating elements comprising first and second sets of radiating elements, each radiating element being configured to operate in a first frequency band that has first and second sub-bands. The second set of radiating elements is located above and/or below the first set of radiating elements. The antenna further includes a feeding assembly that is configured to feed first RF signals that are in the first sub-band and second RF signals that are in the second sub-band to the column of radiating elements, where the feeding assembly is configured to partially attenuate sub-components of the second RF signals that are fed to the second set of radiating elements more than sub-components of the first RF signals that are fed to the second set of radiating elements.

Base station antennas include an externally accessible active antenna module releasably coupled to a rear of the housing. The base station antenna housing has a passive antenna assembly that cooperates with the active antenna module.