Abstract:
A system and method for providing a multi-layer, high density wireless communication architecture is disclosed. An example of a transceiver module is provided to better demonstrate this system and method. The transceiver module comprises a transmitting layer having a top portion and a bottom portion. A filter layer having a top portion and a bottom portion is also provided, wherein the top portion of the filter layer is adjacent to the bottom portion of the transmitting layer. A logic layer having a top portion and a bottom portion is provided, wherein the top portion is adjacent to the bottom portion of the filter layer and wherein logic is located on the bottom portion of the logic layer. A series of via structures of connected at specific locations of the transceiver module to allow for electrical connections between the transmitting layer and the filter layer, and the filter layer and the logic layer. Shield layers are also provided to prevent harmful electronic coupling between layers.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention generally relates to the architecture of wireless communication systems and, more particularly, to decreasing the size of wireless communication systems.  
         BACKGROUND OF THE INVENTION  
         [0002]    Advancements in technology have led to smaller electronic devices having greater functionality. One example of a field of technology where this is demonstrated is within the telecommunication field. The increase of functionality required by communication devices, such as, but not limited to, wireless communication devices, provides an architectural obstacle due to the number of discrete and bulky components required to enable such functionality.  
           [0003]    Current increases in demand for higher data rates and broadband transmission require high performance transceivers. High frequency components are typically used to provide high data rates in communication devices. In addition, low-cost transceivers are desirable for wireless communication devices in order to prevent excessive increases in the cost of these devices. Unfortunately, there is a deficiency of economical high frequency components for low-cost transceivers.  
           [0004]    With the decrease in size of communication devices, the size of components within the communication devices, such as transceivers, are also required to decrease in size. The current drawbacks of most commercially available transceivers are their relatively large size, heavy weight, and separately located modules. If these commercially available transceivers were to be used in communication devices where compactness is desirable, such as, cellular phones, portable wireless modems and local area network (LAN) cards, then it would not be possible to decrease their size. Therefore, transceiver size is an architectural obstacle in constructing smaller communication devices.  
           [0005]    Components located within transceivers that contribute to architectural obstacles include, but are not limited to, antennas and filters. Unfortunately, these components also require large amounts of space within the communication device. Therefore, since antennas and filters require additional space, they place unwanted limitations on the size of communication devices.  
         SUMMARY OF THE INVENTION  
         [0006]    In light of the foregoing, the preferred embodiment of the present invention generally relates to a system and method for providing a multi-layered high density integrated wireless communication architecture.  
           [0007]    Generally, to illustrate an example of use of the multi-layer, high density wireless communication architecture, a transceiver module is provided herein. The architecture utilized for the transceiver comprises a transmitting layer having a top portion and a bottom portion. A filter layer having a top portion and a bottom portion is also provided, wherein the top portion of the filter layer is adjacent to the bottom portion of the transmitting layer. A logic layer having a top portion and a bottom portion is provided, wherein the top portion is adjacent to the bottom portion of the filter layer and wherein logic is located on the bottom portion of the logic layer.  
           [0008]    The present invention can also be viewed as a method for providing a high density integrated transceiver. In this regard, the method can be broadly summarized by the following steps: fabricating a transmitting layer having a top portion and a bottom portion; fabricating a filter layer below said bottom portion of said transmitting layer, wherein said filter layer comprises a top portion and a bottom portion, and wherein said top portion of said filter layer is adjacent to said bottom portion of said transmitting layer; and fabricating a logic layer below said bottom portion of said filter layer, wherein said logic layer comprises a top portion and a bottom portion, and wherein said top portion of said logic layer is adjacent to said bottom portion of said filter layer and wherein logic is situated on said bottom portion of said logic layer.  
           [0009]    The invention has numerous advantages, a few of which are delineated here after as examples. Note that the embodiments of the invention, which are described herein, possess one or more, but not necessarily all, of the advantages set out hereafter.  
           [0010]    One advantage of the invention is that it provides capability for decreasing the size of wireless communication devices without decreasing functionality.  
           [0011]    Another advantage is that it allows antennas and filters to be included in wireless communication devices with minimal space requirements.  
           [0012]    Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention, as defined by the accompanying claims.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The present invention will be more fully understood from the detailed description given below and from the accompanying drawings of the preferred embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments enumerated, but are for explanation and for better understanding only. Furthermore, the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention. Finally, like reference numerals in the figures designate corresponding parts throughout the several drawings.  
         [0014]    [0014]FIG. 1 illustrates an environment in which a multi-layer, high density transceiver module may be implemented.  
         [0015]    [0015]FIG. 2 illustrates a series of examples of wireless communication devices that may utilize the transceiver module of FIG. 1.  
         [0016]    [0016]FIG. 3 further illustrates the transceiver module of FIG. 1.  
         [0017]    [0017]FIG. 4 illustrates an alternative fabrication of the transceiver module of FIG. 3.  
         [0018]    [0018]FIG. 5 is a cross-sectional view illustrating a possible way of connecting the transceiver module of FIG. 3 and a PCB.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    The present disclosure provides an example of multi-layer, high density transceiver module to demonstrate use of the present multi-layer, high density integrated wireless communication architecture. It should be noted that the present multi-layer density integrated wireless communication architecture may be used for other devices and modules besides transceiver modules. Examples of such devices and modules include, but are not limited to, cellular phones, wireless modems, wireless LAN modules, satellite transmit and receive assemblies, and automotive radars.  
         [0020]    Turning now to the drawings, wherein like reference numerals designate corresponding parts throughout the drawings, FIG. 1 illustrates an environment in which the multi-layer, high density transceiver module  100  may be implemented. As shown by FIG. 1 a printed circuit board (PCB)  102  is utilized comprising functionality required by a wireless communication device. It should be noted that the present transceiver module  100  may instead be located on an application specific integrated circuit (ASIC).  
         [0021]    The transceiver module  100  may be fabricated by using a low-temperature co-fired ceramic (LTCC) process, or any other fabrication process. LTCC is attractive for use in RF applications since low loss transmission line and high Q passives can be realized. Use of the LTCC process, and integration of an antenna (further discussed hereinbelow), preferably a cavity-backed patch antenna, provides an ultra compact and highly integrated transceiver module  100 .  
         [0022]    [0022]FIG. 2 provides a series of examples of wireless communication devices that may utilize the transceiver module  100 . Examples of such devices include, but are not limited to, cellular phones, wireless modems, wireless LAN modules for hand-held computers, satellite transmit and receive assemblies, and automotive radars.  
         [0023]    Returning to FIG. 1, the transceiver module  100  may be provided at any location of the PCB  102  in a manner similar to other chips and electronic components that may be located on the PCB  102 . The PCB  102  preferably comprises an edge connector  104  for connecting the PCB into a wireless communication device. Also illustrated by FIG. 1 are multiple chips and electronic devices  106  that may be required by the transceiver module  100 .  
         [0024]    The transceiver module  100  of the present invention can be implemented in software, firmware, hardware, or a combination thereof. In the preferred embodiment of the invention, which is intended to be a non-limiting example, the transceiver module  100  is designed in software that is executed by a computer, for example, but not limited to, a personal computer, workstation, minicomputer, or mainframe computer, and then fabricated. Examples of software that may be used to design the transceiver module  100  include, but are not limited to, Agilent Advanced Design System, High-Frequency Structure Simulator (HFSS), Microwave Office, Sonnet Software, and IE3D.  
         [0025]    The software used to design the transceiver module  100 , which comprises an ordered listing of executable instructions for implementing logical functions, can be embodied in any computer-readable medium for use by, or in connection with, an instruction execution system, apparatus, or device such as a computer-based system processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “computer-readable medium” can be any means that can contain, store, communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus or device.  
         [0026]    The computer-readable medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable programmable read-only memory (EPROM or Flash memory) (magnetic), an optical fiber (optical), and a portable compact disk read-only memory (CD ROM) (optical). Note that the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.  
         [0027]    [0027]FIG. 3 further illustrates the transceiver module  100  of FIG. 1, in accordance with the preferred embodiment of the present invention. A key feature of the transceiver module  100  illustrated is the optimal use of vertical integration of various components which is described in detail herein below. The transceiver module  100  of FIG. 3 comprises an antenna portion  202 , a pre-select filter portion  232 , and a logic portion  292 .  
         [0028]    The antenna portion  202  of the transceiver module  100  comprises a top portion  204  and a bottom portion  206 , wherein antenna logic  208  resides on the top portion  204 . The top portion  204  of the antenna portion  202  resides as the top most portion of the transceiver module  100 , thereby establishing a direct interface between the antenna logic  208  and air to assist in signal reception and transmission of the antenna logic  208 . Preferably, the antenna logic  208  is fabricated in either a micro-strip patch or dielectric configuration. However, other configurations may also be substituted for fabrication of the antenna logic  208 .  
         [0029]    The antenna logic  208  may be fabricated upon the antenna portion  202  by utilizing a conductive material such as, but not limited to, gold or other metals with high conductivity such as copper and silver. Methods of placing the conductive material on the antenna portion  202  may include, but is not limited to, spinning, etching, sputtering, screen-printing, evaporating and micro-machining.  
         [0030]    The antenna portion  202  also comprises an antenna portion via hole  212  that extends through the top and bottom portions  204 ,  206  of the antenna portion  202  and intersects the antenna logic  208 . The antenna portion via hole  212  provides a vehicle for implementation of a first via structure  302  that provides a conductive connection between the antenna portion  202  and a first pre-select filter portion  234 , through a first shielding layer  224 . Via structures provided herein enable electrical communication throughout the transceiver module  100 .  
         [0031]    The first shielding layer  224  is located below the antenna portion  202  of the transceiver module  100  and comprises a top portion  226  and a bottom portion  228 . The first shielding layer  224  prevents electronic coupling between the antenna portion  202  and the first pre-select filter portion  234 . Preferably, the first shielding layer  224 , as with all shielding layers provided herein, is fabricated of gold and/or other metals with high conductivity such as copper and silver. The shielding layers may be fabricated from other conductive materials as well. The first shielding layer  224  also comprises a via hole which extends through the top and bottom portions  226 ,  228  of the first shielding layer  224  for allowing implementation of the first via structure  302 .  
         [0032]    The first pre-select filter portion  234  is located beneath the first shielding layer  224 . Preferably, a stripline topology is used to provide a pair of tracers on a top portion  238  of the first pre-select filter portion  234 , wherein a first tracer  242  is an input to the first pre-select filter portion  234  and a second tracer  244  is an output from the first pre-select filter portion  234 . The input  242  of the first pre-select filter portion  234  is electronically connected to the antenna logic  208  via the first via structure  302 . The tracers may be fabricated by use of gold and/or other metals with high conductivity such as copper and silver.  
         [0033]    A second shielding layer  252  is located below the first pre-select filter portion  234  and comprises a top portion  254  and a bottom portion  256 . The second shielding layer  252  prevents electronic coupling between the first pre-select filter portion  234  and a second pre-select filter portion  272 . The second shielding layer  252  also comprises a via hole which extends through the top and bottom portions  254 ,  256  of the second shielding layer  252  for allowing implementation of a second via structure  304 .  
         [0034]    The second pre-select filter portion  272  is located beneath the second shielding layer  252 . Preferably, a stripline topology is used to provide a pair of tracers on a top portion  273  of the second pre-select filter portion  272 , wherein a first tracer  274  is an input to the second pre-select filter portion  272  and a second tracer  276  is an output from the second pre-select filter portion  272 . The input  274  of the second pre-select filter portion  272  is electronically coupled to the output  244  of the first pre-select filter portion  234  via the second via structure  304 , wherein the second via structure  304  passes through the via hole located within the second shielding layer  252 .  
         [0035]    A third shielding layer  282  is located below the second pre-select filter portion  272  and comprises a top portion  284  and a bottom portion  286 . The third shielding layer  282  prevents electronic coupling between the second pre-select filter portion  272  and the logic portion  292 . The third shielding layer  282  also comprises a via hole which extends through the top and bottom portions  284 ,  286  of the third shielding layer  282  for allowing implementation of a third via structure  306 . Therefore, the first, second and third shielding layers  224 ,  252 ,  282 , in combination with the first and second pre-select filter portions  234 ,  272 , make the pre-select filter portion  232 . It should be noted that the pre-select filter portion  232  may have fewer or more pre-select filter portions and fewer, more, or no, shielding portions.  
         [0036]    [0036]FIG. 4 is a diagram illustrating an alternative fabrication of the transceiver module  100  of FIG. 1. As shown by FIG. 4, four additional via structures  287 ,  288 ,  289 ,  291  are implemented for providing additional structural stability for the transceiver module  100 . As such, one via structure extends through each corner of the first, second and third shielding layers  224 ,  252 ,  282 , and the first and second pre-select filter portions  234 ,  272 , and the logic portion  292 . Of course, alternate structures may be implemented wherein fewer or more via structures are used.  
         [0037]    Returning to FIG. 3, the logic portion  292  of the transceiver module  100  is located below the third shielding layer  282  and comprises a top portion  294  and a bottom portion  296 . The bottom portion  296  of the logic portion  292  comprises chips and other components required to perform functionality required by the transceiver module  100 . It should be noted that FIGS. 3 and 4 show the bottom portion  296  of the logic portion  292  facing upward for illustration purposes, however, as noted by the numbering of the top and bottom portions  294 ,  296 , the bottom portion  296  of the logic portion  292  is intended to face downward and away from the pre-select filter portion  232 . Preferably, monolithic microwave integrated circuit (MMIC) chips  322  and on-board integrated passive components  324  are located on the bottom portion  296  of the logic portion  292 . For example, two MMIC attachments that may be used to connect to the MMIC chips  322  and on-board integrated passive components  324  to the logic portion  292  include the use of bond wires on chips  322  that are dropped in a cavity to ensure a short electrical path and minimize parasitics, and flip chip bumps. The logic portion  292  also comprises a via hole wherein the third via structure  306  is situated, thereby providing electrical connection between the second pre-select filter portion  272  and the logic portion  292 .  
         [0038]    The logic portion  292  is fabricated of a series of dielectric layers, three being illustrated by FIG. 3. It should be noted that additional, or fewer dielectric layers may be used to fabricate the logic portion  292 . In addition, additional logic portions may be provided within the multi-layer, high density integrated communication architecture. In fact, the number of layers need only be limited by the device implemented by the multi-layer, high density architecture, which, in accordance with the present example, is a transceiver module  100 .  
         [0039]    The availability of additional dielectric layers makes possible the three dimensional deployment of other integrated passives such as, but not limited to, baluns, lumped inductors, capacitors, and resistors, as well as intermediate frequency (IF) or low pass filters, for example, in the case of a superheterodyne or direct conversion scheme, respectively. The integrated balun can be interfaced to a push-pull power amplifier or a mixer. The input matching of a low noise amplifier or input and output matching of a power amplifier, typically done by discrete passives, can be conveniently replaced by their on-board integrated version.  
         [0040]    The LTCC process used offers screen printing and low loss stacked via processes as well as high conductivity metalization useful for high frequency applications. Various LTCC materials are presently available. Table 1 provided herein below provides a summary of a series of widely used LTCC and high temperatured co-fired ceramics (HTCC) materials and their respective properties supplied by manufacturers.  
                                                                     TABLE 1                                   Thermal                               Conductivity   CTE   Tape           Dielectric   Loss   (W/m.K) at   (1/° C.) at   Thickness       Material   Constant   Tangent   293K   25-200° C.   (mils)   Metal                                HTCC   9.6   0.0015   23   7.2 × 10 −6     4-20    Tungsten           (1 MHz)   (1 MHz)       Dupont&#39;s   7.8   0.0015   3   5.8 × 10 −6     5-8.3   Silver/Gold       951 AT   (1 MHz)   (1 MHz)       Dupont&#39;s   7.5   0.0015   3   5.3 × 10 −6     5-8.3   Silver/Gold       943 AT   (1 MHZ)   (1 MHz)       Ferro A6-   5.9   &lt;0.002      3     7 × 10 −6     3.7-7.4     Silver/Gold       M   (10 MHz)    (10 MHz)                   
 
         [0041]    [0041]FIG. 5 is a cross-sectional view illustrating a possible way of connecting the transceiver module  100  and the PCB  102 . The transceiver module  100  of FIG. 3 may be interfaced to the PCB  102  via ball-grid-array interconnects with the antenna  202  portion facing upward and the bottom portion  296  of the logic portion  292  facing downward. Referring to FIG. 5, a first ball grid interconnect  352  and a second ball grid array interconnect  354  connect the bottom portion  296  of the logic portion  292  to the PCB  102 . Preferably, ball dimensions of about 30 mils or greater allow sufficient space between the attached MMIC chips  322  to the PCB  102  even when flip chip topology is chosen as the attachment option.  
         [0042]    Therefore, use of the multi-layer, high density communication architecture replaces discrete elements typically incorporated in the conventional topology by integrating them on the PCB  102 . It yields a considerably smaller module, which is extremely important for portable wireless electronic devices. The reduction in cost as a result of implementing the topology not only comes from the fact that the circuit module occupies smaller area, but also because it eliminates the needs for discrete elements and therefore, reduces the assembly time also. In addition, the reliability of a module implemented in this architecture also improves since solder joint failure is reduced due to the lack of use of discrete elements. Other elements may be located within the transceiver module  100  since they may be embedded inside the PCB  102 . Such elements may include, but are not limited to, filters, additional antennas, inductors and capacitors. This would also be true if the multi-layer, high density communication architecture were used for a different module, besides the transceiver module  100  provided for herein.  
         [0043]    It should be emphasized that the above-described embodiments of the present invention, particularly, any “preferred” embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.