Abstract:
A point-to-point radio communications device, with an integrated antenna-IC module, includes highly-directional antenna elements and silicon CMOS-based ICs in plastic packaging material. The high-gain horn-type antenna includes two sections made of molded plastic and covered in a metallic coating. When combined, the two sections form an aperture and an opening on a face. The face of the antenna element can be mounted directly to an integrated circuit with an antenna coupling element, such that the aperture forms a horn-IC module. The module can be completely enclosed in a plastic-packaging environment using low-cost approach. The antenna-IC module can be manufactured as an integral part of a case for a point-to-point wireless electronic device such as a mobile video phone or a set-top box with tens of gigabits of video downloading capability.

Description:
FIELD 
   The present invention relates generally to highly-directional antenna integration with silicon integrated circuits, and more specifically to millimeter wave high-gain horn antenna integration with CMOS ICs. 
   BACKGROUND 
   Current trend in utilizing 57-64 GHz high-data-rate spectrum for wireless communication calls for new, low-cost radios, integrated with set-top boxes or mobile platform/handsets. Energy propagation in this mm-wave band has unique characteristics which enables excellent immunity to interference, highly-secured communication, frequency re-use, etc. For low-cost point-to-point communication at this frequency range, highly directional, high-gain antennas are desired for integration with complementary metal oxide semiconductor (CMOS)-technology-based radios. 
   Waveguide horn structures are typically used for high gain, directional antennas at millimeter (mm) wave frequencies. Currently available metal horns are bulky, heavy, expensive, and non-ideal for planar, integrated circuit (IC) integration. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows perspective views of horn antenna element sections; 
       FIG. 2  shows an integrated circuit top view and cross-section with CMOS based IC to antenna transition example; 
       FIG. 3  shows a modular combination of CMOS integrated circuit and horn antenna element; and 
       FIG. 4  shows mobile communications device with embedded directional antenna integrated radio. 
   

   DESCRIPTION OF EMBODIMENTS 
   In the following detailed description, reference is made to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that the various embodiments of the invention, although different, are not necessarily mutually exclusive. For example, a particular feature, structure, or characteristic described herein in connection with one embodiment may be implemented within other embodiments without departing from the spirit and scope of the invention. In addition, it is to be understood that the location or arrangement of individual elements within each disclosed embodiment may be modified without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, appropriately interpreted, along with the full range of equivalents to which the claims are entitled. In the drawings, like numerals refer to the same or similar functionality throughout the several views. 
     FIG. 1  shows perspective views of horn antenna sections. Horn antenna sections  110  and  140  each have an axis shown at  116  and  146 , respectively. Horn antenna section  110  has an interior face  112  parallel to axis  116 , and horn antenna section  140  has an interior face  142  parallel to axis  146 . 
   Horn antenna section  110  has a notch in interior face  112  parallel to axis  116 . The notch in section  110  has planar faces  114 . Although the notch in section  110  is shown with four planar faces, this is not a limitation of the present invention. Any number of planar faces may be included. Horn antenna section  140  has a notch in interior face  142  parallel to axis  146 . The notch in section  140  has a semicircular cross section  144 . Other cross-section shapes may be utilized without departing from the scope of the present invention. For example, a cross-section of a notch may have any geometric shape. 
   The notches in sections  110  and  140  may have non-uniform depths. For example, the notch in horn antenna section  110  may be deeper at end  115  than at end  117 . Also for example, the notch in horn antenna section  140  may be deeper at end  145  than at end  147 . As described further below, when two sections with non-uniform depth notches are mated, the notches may form an angular or conical horn aperture. 
   In some embodiments, sections  110  and  140  are made of molded plastic. For example, the sections may be molded in the shape shown, or may be molded with a solid interior face and the notch may be machined. Portions of horn antenna sections  110  and  140  may be covered with a conductive material. For example, the notches and inner sides in sections  110  and  140  may be covered with a metallic material. In some embodiments, all of sections  110  and  140  are covered in a metallic material. 
   In some embodiments, a horn antenna may be made when two sections are combined such that the interior faces mate, and the notches form an aperture. For example, section  120  may be identical to section  110 , and they may be coupled such that their interior faces mate. The notches in sections  110  and  120  form an aperture with openings on two ends. An exploded view of an octagonal opening  124  is shown at end  122  of the horn antenna formed by sections  110  and  120 . Also for example, section  150  may be identical to section  140 , and they may be coupled such that their interior faces mate and an aperture is formed with an opening on two ends. An exploded view of a circular opening  154  is shown at end  152  of the horn antenna formed by sections  140  and  150 . 
   Apertures in the horn antennas may be diagonal, conical, or any other shape. For example, when the notches in sections  110  and  120  have non uniform depths, a diagonal shaped aperture may be formed in the resulting horn radiator. Also for example, when the notches in sections  140  and  150  have non-uniform depths, a conical shaped aperture may be formed in the resulting horn antenna. 
   In some embodiment, only the surface area of the notches are metallized. In these embodiments, the interior surfaces of the aperture are radiative. In other embodiments, the entire antenna radiator sections are metallized. This insures good metal coverage at the joints between reflector sections as well as good electrical connectivity. The ends of the horn may be metallized. For example, ends  122  and  152  have metallic coatings to allow the ends to be soldered to an integrated circuit having exposed metal. Various embodiments of horn antenna radiators coupled to CMOS-based integrated circuits are described below with reference to  FIG. 3 . 
     FIG. 2  shows an integrated circuit to highly directional antenna transition top view and cross section. As an example, top view  210  and cross sectional view  220  show metal face  212 , patch  214 , and antenna feed line  216 . Top view  210  also shows cross slots  218  in patch  214 , and cross section view  220  also shows metal layer  224 . 
   Metal face  212 , patch  214 , metal layer  224 , and feed line  216  are all formed on metal layers within the integrated circuit. As shown in cross section view  220 , the metal layers are separated by insulating layers. The integrated circuit structure shown in  FIG. 2  may be manufactured using dielectric and metal layers on top of the CMOS-based silicon IC substrate. 
   Metal face  212  is formed in a geometric pattern. Metal face  212  is shown as octagonal in shape in  FIG. 2 , but this is not a limitation of the present invention. For example, metal face  212  may be circular, oval, hexagonal, or any other geometric shape. In general, the geometric pattern of metal face  212  matches the geometric pattern of a horn antenna radiator opening to which it will be mated, although the various embodiments of the invention also contemplate mating dissimilar shaped metal faces and horn radiator openings. 
   In operation, feed line  216  is excited with a signal, and energy radiates through the hole in metal layer  224 , and through cross-slot  218  in patch  214 . A horn antenna may be attached to metal face  212 , thereby creating a directional antenna-IC module. The dimensions of the various elements in the integrated circuit and the size of the horn may be modified to tune the antenna structure to various frequencies. For example, the elements may be sized to tune the antenna structure to mm-wave frequencies. 
     FIG. 3  shows a combination of CMOS-based silicon integrated circuit and horn antenna that are presented in  FIGS. 2 and 1 . Integrated circuit  220  is described above with reference to  FIG. 2 . Horn antenna  310  has an aperture  312  between two ends  320  and  342 . End  342  of horn antenna  310  is coupled to integrated circuit  220  such that energy radiated through patch  214  is directed by aperture  312 . 
   Horn antenna radiator  310  may be attached to integrated circuit  220  using any suitable method. For example, in some embodiments, end  342  is metal, face  212  is metal, and horn antenna  310  is soldered to integrated circuit  220 . Also for example, in some embodiments, horn antenna  310  is glued with a conductive material to CMOS integrated circuit  220 . 
   Horn antenna  310  may be any of the horn antenna embodiments disclosed herein. For example, horn antenna  310  may be any of the horn antenna made up of sections as shown in  FIG. 1 . The CMOS IC can be mounted on any plastic materials,  355 . PCB type plastic boards can be used as  355 . Section  350  presents the junction between  355  and metallized plastic-horn faces,  342 . Thermal vias,  360 , may be used, if necessary in the modular assembly. 
     FIG. 4  shows a mobile communications device. Mobile communications device  400  includes horn antenna  320 . In some embodiments, horn antenna radiator assemblies  370 ,  380 ,  390  are manufactured separately from, and then attached to, the different parts of the body of the mobile communications device  400 . Also in some embodiments, the two pieces of horn antenna  320  are manufactured as part of two pieces of the body of mobile communications device  400 . The aperture in horn antenna  320  is then formed when the body for mobile communications device is assembled. Horn antenna  320  is coupled to an integrated circuit as shown in  FIG. 3 . Horn antenna assemblies  370 ,  380 ,  390  may be mounted at different parts of the mobile communications device, as necessary for the communication. 
   Mobile communications device  400  may be any type of device that includes a horn antenna. For example, mobile communications device  400  may be a mobile video downloading device, mobile phone, a personal digital assistant, a portable music player, or any other mobile communications device. Horn antenna  320  may be coupled to an antenna used for any type of communications. For example, the antenna may support signal transmission and reception in support of wireless high definition multimedia interface (HDMI), point-to-point personal area networks (WPAN) type of applications. 
   The antenna-CMOS-IC embodiments may be mounted on a set-top box similar to the mobile device for high-data rate communications, such as, video downloading. 
   Although the present invention has been described in conjunction with certain embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention as those skilled in the art readily understand. Such modifications and variations are considered to be within the scope of the invention and the appended claims.