An improved printed-circuit cross-slotted antenna for satellite communication. The antenna comprises a dielectric substrate covered with conductive material on a first ground plane side and on a second radiating side. The periphery edges of the first and second sides electrically interconnect the sides. The radiating side includes a first and a second slot with the conductive material removed and the substrate exposed. Conductors pass through the crossed slot antenna from the first side to the second side with connections only to the second side. Electrical signals to be radiated from the second side are connected to the connectors. The second side radiates the Electrical signals in a pattern according to the configuration of the slots.

FIELD OF INVENTION 
This invention relates to radio wave communications and antennas, and more 
specifically to-plural slot type antennas for satellite communications. 
BACKGROUND OF THE INVENTION 
The closest prior art can be found in U.S. Pat. No. 4,916,457. This patent 
by two of the three inventors of the instant invention is directed to a 
similar type antenna which teaches a printed circuit cavity-backed 
crossed-slotted conductive element having two legs of each slot coupled by 
stripling feeders to a radio communication device. The feeders supply the 
radio frequency signal with a 180 degree phase shift in order to cancel 
cross-coupling from one leg to another around the intersection. The 
conductive element and the stripling feeders are mounted on separate 
substrates which are sandwiched together with other elements to provide 
shielding and mechanical protection. The crossed-slot design reduces space 
and structure required for mobile application while achieving good 
performance. When mounted in an array, the crossed slot antenna may be 
directionally tuned to a specific satellite/frequency/direction via pin 
diode phase shifters. 
Additional prior art related antennas can be found in the references cited 
in the above referenced United States patent. 
The instant invention is an improvement to the type of printed-circuit 
crossed-slot antenna taught by the above referenced United States patent. 
SUMMARY OF THE INVENTION 
The invention is directed to a uniquely configured printed-circuit 
crossed-slot antenna which comprises a non-metallic substrate with the 
entire outer surface including the edge surfaces coated with a thin layer 
of an electrically conductive material such as, aluminum, copper, silver, 
gold, platinum or other suitable high electrical conductive materials 
metallic or otherwise. The cavity radiating side of the substrate includes 
a crossed-slot as defined in U.S. Pat. No. No. 4,916,457 with differently 
configured slot ends. Plated through apertures which begin at and are 
insulated from the conductive material covered side of the non-metallic 
substrate electrically connect to the conductive material portion of the 
crossed-slot side of the non-metallic substrate. These apertures provide 
radio frequency energy into or out of the cavity and in turn, this energy 
being received or radiated out to space from the crossed-slots. The 
apertures are spaced apart substantially 90 degrees and are positioned 
substantially 45 degrees from a longitudinal and transverse center lines 
through the slots. The central conductor of the signal feed elements of 
four connectors passes through without electrical contact with the 
conductive covered side of the conductive material covered or ground plane 
side of the substrate to the slotted radiating side thereof. One central 
conductor of the feed element is electrically connected to each of the 
plated through apertures for excitation of the antenna cavity formed by 
the crossed-slots. The ground plane connection of each of the connectors 
is electrically connected to the conductive material of the solid material 
or ground plane side of the substrate and the signal feed elements are 
electrically connected to the conductive material of the radiating side of 
the antenna. The operating frequency of the antenna cavities is determined 
by the dimensions of the substrate, slot configuration and the thickness 
and dielectric rating of the substrate medium. The individual elements, 
ie. the substrate defined above, can be electrically formed as an array, 
as defined in the above cited United States Patent. 
An object of this invention is to provide a more simplified antenna cavity 
structure limited to a single layer substrate. 
An other object of this invention is to provide a probe fed crossed-slot 
antenna. 
An other object of this invention is to provide a crossed-slot antenna with 
increased bandwidth over the prior art crossed-slot antennas. 
Yet other object of this invention is to provide a crossed-slot antenna 
with increased efficiency over the prior art crossed-slot antennas. 
An other object of this invention is to provide a simplified antenna 
structure with reduced manufacturing costs. 
These and other objects and advantages of the present invention will become 
apparent to those skilled in the art after considering the following 
detailed specification in which the preferred embodiment is described in 
conjunction with the accompanying drawing Figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawing Figures and specifically to drawing FIGS. 1-3 
which depict the first preferred embodiment of the crossed-slot antenna 10 
of invention and drawing FIGS. 4-6 which depict a second embodiment of the 
crossed-slot antenna. The antenna 10 comprises a central dielectric 
substrate 12a, 12b (see drawing FIG. 6) formed from a non-metallic 
insulation material having a suitable dielectric for the desired resonate 
frequency of the antenna cavity 14. The thickness of the dielectric 12a 
and 12b is determined by the type of dielectric material and the frequency 
at which the antenna is designed to operate. The surfaces of the entire 
substrate including the edges 16 thereof are conductively interconnected 
with a suitable highly electrically conductive material such as, for 
example, aluminum, cooper, silver, gold, platinum or the like. The two 
opposed surfaces covered by the highly electrically conductive material 
are either interconnected by plating the substrate periphery edges 16 or 
plated through holes 17 around the periphery edges between the two 
surfaces of the substrate by a process well known in the printed circuit 
art. One surface 18 (the ground plane surface) is completely covered with 
conductive material and the opposite surface 20 (radiating surface) is 
likewise completely covered with conductive material except for the 
crossed-slot cavity 14 formed by removing the conductive material coating 
from the substrate. The cavity is formed by crossed-slots with selectively 
configured slot distal ends 24a, 24b. As shown in drawing FIG. 2, the ends 
24a of the slots are rectangular in form while the distal ends of the 
slots 24b are shown in FIG. 5 are curvilinear in form. Various different 
slot end configurations can be chosen for various different specific 
radiation properties. 
A plurality of four plated through apertures 26a, 26b, 26c and 26d extend 
and are insulated from the surface 18 to the surface 20. The plated 
through apertures are electrically insulated from the surface 18 by means 
of spacing or insulation material (not shown) and connect at their 
opposite ends to the surface 20. The apertures 26 are substantially spaced 
90 degrees apart along approximately the 0 degree (referenced from the top 
of the drawing Figures), 90 degree, 180 degree and 270 degree axis of the 
substrate 10 with the slots intersecting at their center and the center of 
the substrate with one slot extending between the second to third quadrant 
and the second slot extending between the first and third quadrant. The 
slots are positioned substantially equally between the apertures. 
A conventional microwave connector 28 with a central connector 32 
interconnected to the plated through aperture and a conductive lead 
therefrom may extend through the aperture while being electrically 
insulated from surface 18 and electrically connected to the surface 20. 
The outer shell 34 of connector 32 is electrically connected to the 
surface 18 of the ground plane side of the substrate. 
The apertures 26a-26d may be spaced at different selected distances from 
the outer edge of the substrate as shown in drawing FIGS. 1, 2, 4 and 5. 
The spacing of the apertures like the outer distal end configuration of 
the slots and selection of the dielectric material determine the frequency 
of the antenna 10 and the configuration of the transmitted wave pattern 
therefrom. 
As fully discussed in the fore mentioned U.S. Pat. No. 4,916,457, the legs 
of each slot are fed by a pair of central conductors (positive) 32. A 
first pair of central conductors supply radio frequency signal, as taught 
by the patent or in any other manner suitable for the purpose intended, to 
each leg of each slot 180 degrees out of phase from the opposite leg 
central conductors. 
The conductive material can be plated on the substrate as in stripline 
technology, adhered thereto or attached thereto in any manner suitable for 
the purpose intended. 
As can be seen in drawing FIG. 5, the intersection of the two legs includes 
a rectilinear configured transition area 36 which is designed to effect 
the operating frequency of the antenna. Other transition configurations 
can be used at the intersection of the legs to effect yet different 
radiation configurations. 
It should be understood that the antenna, as herein after claimed, can be 
used for receiving radio frequency signals as well as for transmitting 
radio frequency signals. 
While the geometry of the preferred embodiments have been described many 
other geometries could be devised to practice this invention. 
While the preferred embodiments of the invention have been shown and 
described, changes and modifications may be made without departing from 
the spirit and scope of the appended claims without departing from the 
spirit and scope of this invention.