High gain compact scanning personal communication system array

An endfire monopole array in a low cross section, low profile package with the area used being vertical or tube-like. The array is aerodynamically shaped on one or more sides in order to minimize wind resistance. The antenna array includes an RF transparent housing having a tapered end portion which is substantially "V" shaped, a first plurality of parallel endfire monopole antenna elements secured to a stripline or microstrip within the housing, each antenna element thereof extending in a first direction and a second plurality of parallel endfire monopole antenna elements secured to a stripline or microstrip within the housing, each antenna elements of the second plurality extending in the first direction, the first plurality being spaced from the second plurality in the first direction. An energy feeding structure is coupled to the antenna elements, with a dielectric layer disposed over that structure and a ground plane disposed over the dielectric layer. A line bisecting the "V" is normal to the first direction.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a scanning array for use in conjunction with 
personal communication systems (PCS) and, more specifically, to a compact 
antenna for use in conjunction with mobile communication systems. 
2. Brief Description of the Prior Art 
In the field of mobile communication, such as, for example, cellular 
telephone systems which operate generally in the 850 MHz and 1900 MHz 
frequency regions, it is necessary to provide a multiplicity of antennas 
throughout the area covered by the system so that a user of the system has 
access thereto at all locations within the covered area. The quality of 
communication depends in part upon the gain of the antenna arrays and the 
number and proximity of antenna arrays to each other within the covered 
area. Gains in excess of 21 dBli are consistently requested by users. 
Improved gain is constantly being sought, especially in the 1900 MHz 
frequency region. The prior art has generally used patch and dipole 
antennas in a flat or "billboard" style with the "billboard" plane being 
vertical for this purpose with the antenna elements extending outwardly 
horizontally or parallel to the ground to provide the proper pattern for 
these types of antenna elements. Such antenna arrays generally have 
dimensions of about 3 feet by about 5 feet or more to obtain the required 
gain. 
Two methods of improving access to the system have been to increase the 
number of antenna arrays in the covered area and/or to increase the gain 
of the system antenna arrays, this being accomplished by increasing the 
surface areas of the individual antenna arrays. While an increase in 
antenna array area does and has improved access to the mobile 
communication systems, such larger area antenna arrays become increasingly 
unsightly with increase in size, especially for tower top applications in 
urban environments where their use can also be subject to adverse zoning 
requirements. Such larger area antennas also become more subject to wind 
load effects with increase in exposed area. Such wind load effects also 
have a deleterious effect on the electrical properties of the antenna. It 
is therefore apparent that an improved type of antenna system which 
eliminates or at least minimizes the above noted problems of the prior art 
is highly desirable. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, the above described problems of 
the prior art are minimized. This is accomplished by providing an antenna 
array for use in conjunction with PCS systems and the like which has a low 
profile and smaller cross sectional area as compared with the prior art 
"billboard" type antenna of the same gain and appears in shape closer to 
that of a light fixture to provide improved aesthetics. 
Briefly, the antenna array in accordance with the present invention 
utilizes a plurality of endf ire monopole antenna elements which transmit 
energy in a direction normal to their major axis. The antenna array has a 
low cross section, low profile package with the area used being vertical 
or tube-like as opposed to the billboard shape and patch or dipole arrays 
of the prior art. The monopole antenna elements are stacked in plural 
planes above and below each other rather then being all in one plane as in 
the prior art and preferably extend upwardly and/or downwardly in a 
direction generally normal to the ground though the antenna array will 
operate, but less efficiently, as long as a major component of the major 
axes of the antenna elements is normal to the ground. In addition, the 
radome housing the array is aerodynamically shaped on one or more sides in 
order to minimize wind resistance. 
The antenna array includes an RF transparent housing having a tapered end 
portion which is preferably substantially "V" shaped, a first plurality of 
parallel endfire monopole antenna elements preferably secured to a 
stripline or microstrip within the housing, each antenna element thereof 
extending in a first direction and a second plurality of parallel endfire 
monopole antenna elements secured to a stripline or microstrip within the 
housing, each antenna elements of the second plurality extending in the 
first direction, the first plurality being spaced from the second 
plurality in the first direction. An energy feeding structure in the form 
of the stripline or microstrip is coupled to the antenna elements, with a 
dielectric layer disposed over that feeding structure and a ground plane 
disposed over the dielectric layer. A tapered end portion preferably is 
disposed so that a line bisecting the "V" is normal to the first 
direction.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring first to FIG. 1, there is shown a typical antenna array in 
accordance with the present invention. The antenna array 1 is disposed on 
a pole 3 which is anchored in the ground 5. The antenna 1 is coupled to a 
communication system in standard manner which forms no part of this 
invention and will not be discussed herein. The antenna 1 includes a 
plurality of vertically extending dipole antenna elements 7 which will be 
discussed in more detail hereinbelow. 
The antenna 1 is shown in greater detail in FIGS. 2a and 2b and includes a 
radome portion 9 of a dielectric material which is transparent to RF in 
the range of interest, such as, for example, fiberglass, and secured to a 
pair of multilayered regions 11 and 13 which retain the dipole antenna 
elements 7. The frequency range for which the dipole antenna elements 7 is 
designed is determined by the height thereof as is well known. The radome 
portion 9 and multilayered portions 11 are in the form of a "V" with the 
dipole antenna elements 7 extending vertically upward from the 
multilayered region 11 and extending vertically downward from the 
multilayered region 13. The radome portion is aerodynamically shaped with 
the curved or bottom portion of the "V" preferably, but not necessarily, 
being essentially pointed to minimize wind resistance. It should be 
understood that an aerodynamically shaped radome portion can be disposed 
on some or all edges to minimize wind resistance in all directions. 
The multilayered regions 11 and 13 are shown in part in greater detail in 
FIG. 3 wherein each multilayered region is shown as having a first feed 
layer 15 formed of an electrical conductor, preferably copper, the layer 
15 preferably being a microstrip or strip line secured to the dipole 
antenna element 7 by, for example, solder 21. The dipole antenna element 7 
is spaced from a ground plane 17, preferably of copper, which is also 
spaced from the feed layer 15 by a layer 19 of any standard dielectric 
material. The dipole antenna element 7 has a major axis extending in a 
vertical direction along the length of said dipole antenna element. 
It should be understood that, though the antenna array is shown in the 
shape of a "V" in the preferred embodiment, that shape is not critical. 
The array can fold back and forth several times, such as in the shape of a 
"W" or two or more "V"s connected together or any other shape which will 
provide compactness and, preferably, lower wind resistance. 
Though the invention has been described with respect to a specific 
preferred embodiment thereof, many variations and modifications will 
immediately become apparent to those skilled in the art. It is therefore 
the intention that the appended claims be interpreted as broadly as 
possible in view of the prior art to include all such variations and 
modifications.