Abstract:
The performance of a dual band meanderline antenna is improved with the addition of a conductive patch. It is well known that a meanderline antenna will have various resonances. A conductive patch capacitively coupled to the meanderline broadens and move the second resonance frequency. Connecting the conductive patch to a coherent power source causes additional bandwidth enhancements.

Description:
RELATED PATENT  
       [0001]    U.S. Pat. No. 6,466,174, issued Oct. 15, 2002, titled “SURFACE MOUNT CHIP ANTENNA, is related to the present invention. The disclosure of U.S. Pat. No. 6,466,174 is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to antenna and, more particularly to an ultra-wide band communication antenna combining meanderline and patch antennas.  
         BACKGROUND OF THE INVENTION  
         [0003]    Wireless devices increase their usefulness with each standardized communication channel on which they can operate. Often, operation on multiple communication channels requires operation on different frequencies bands. For example, 802.11 is grouped into multiple bands of operation. An antenna that operated on 2 of the bands (i.e, dual band) would be more valuable than a single frequency antenna. Further, a tri-band (3 bands) would be more valuable than a dual band.  
           [0004]    Communication frequency bands may overlap or be in sufficiently close proximity that the effect is a wider bandwidth than any one communication channel. Also, wider bandwidths are necessary for some high data rate transmissions, such as video streaming and the like.  
           [0005]    To accommodate these wider bandwidths and multiple communication channels, many wireless devices have incorporated multiple antennas. While this works, it increases the complexity of the wireless device, the size of the wireless device, and the cost to manufacture the wireless device. Another solution would be to provide a log periodic antenna, but log periodic antennas generally require fairly large structure with multiple elements.  
           [0006]    One common antenna useful to operate across multiple bands is a planar inverted F antenna (PIFA). PIFAs provide a good match (without a matching network) at different frequencies simultaneously to allow multiple band operation. However, when bands are close together in frequency, the match becomes difficult to achieve.  
           [0007]    Another problem with the PIFA is that as the size of the PIFA is reduced to accommodate smaller and smaller handheld style devices, the bandwidth of the PIFA shinks as well. In other words, the minimum bandwidth of a PIFA often limits the maximum size reduction. An important measure of antenna bandwidth is called percentage bandwidth, or PBW. PBW is computed as 
             PBW =( f   u   −f   l )/({square root} f   u   f   l )×100  equation #1 
           [0008]    In equation #1, f u  is the upper frequency of the bandwidth. f l  is the lower frequency of the bandwidth. For the typical handheld wireless device, most PIFAs have a 10% PBW.  
           [0009]    Thus, it would be desirable to develop a multi-band antenna having a wide bandwidth.  
         SUMMARY OF THE INVENTION  
         [0010]    To attain the advantages of and in accordance with the purpose of the present invention, antenna assemblies with having a meanderline element and a patch element are provided.  
           [0011]    The foregoing and other features, utilities and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0012]    The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:  
         [0013]    [0013]FIG. 1 is perspective view of a meanderline antenna associated with the present invention;  
         [0014]    [0014]FIG. 2 is a perspective view of a combination meanderline and patch antenna consistent with the present invention;  
         [0015]    [0015]FIG. 3 is a perspective view of another combination meanderline and patch antenna consistent with the present invention;  
         [0016]    [0016]FIG. 4 is a plot relating power to frequency of the combination antenna of FIG. 2; and  
         [0017]    [0017]FIG. 5 is a plot relating power to frequency of the combination antenna of FIG. 3. 
     
    
     DETAILED DESCRIPTION  
       [0018]    The present invention will be described with reference to FIGS.  1 - 3 . FIG. 1 shows a possible meanderline antenna  100  (Meanderline and Meander are used interchangedly in this application). Meanderline antenna  100  includes a conductive trace  102  having a series of parallel elements  104  forming a serpentine configuration. As shown, conductive trace  102  has a length L. A lead  106  formed on one end of conductive trace  102  to provide a feed. A second lead  108  (not required but provided in this embodiment) provides a support lead for mechanical stability and is isolated in this embodiment but may be grounded depending on length L. The meander works with a counterpoise (not shown) which typically forms the ground plane for the RF signal applied to lead  106 . In this embodiment, leads  106  and  108  are off-set from conductive trace  102  so it resides above the substrate plane  110 . The substrate for meanders is typically free from ground. The substrate  110  could be the top layer of a multi-plane PCB that is cleared of metallization on all layers in a keep-out area beneath the meander antenna  100 . It could also be the absence of any material whatsoever in the keep-out area. Meanderline antenna  100  provides multi-band functionality by itself. Resonance in various frequency bands can be accomplished by changing the length of the conductive trace  102 , the distance between parallel elements  104 , and the like.  
         [0019]    It has been discovered that adding a patch element  202  changes the width and resonant frequency of one or more communication bands on which meanderline antenna  100  operates. Such a combination antenna  200  is shown in FIG. 2. Combination antenna  200  includes conductive trace  102  and patch element  202 . As shown, patch element  202  resides in substrate plane  110  parallel to conductive trace  102 . However, patch element  202  could reside anywhere in relation to conductive trace  102 , such as above or below conductive trace  102  as a matter of design choice. As shown, patch element  202  substantially aligns with conductive trace  102 . Patch antenna  202  has a length L′. FIG. 4 shows a possible plot of power vs. frequency for combination antenna  200 . In this case, the antenna has two relatively wide channels of operation channel  1  is around 2.6 GHz and channel  2  is around 5.35 GHz. The specific tuning of channel  1  and channel  2  is exemplary, and could be altered. Further, while patch element  202  is shown substantially aligned with conductive trace  102 , patch element  202  could be angled, off-set, or have different dimensions, such as a shorter length. The principle of the patch is that it provides capacitive coupling of the meander to a metallic body (which may or may not be connected to the meander). It is just the proximity of a piece of metallization, capacitively coupled to the meander that is causing the effect. This embodiment has the patch beneath the meander, but it can be anywhere and any orientation. Another embodiment has the patch/meander combination at an angle to a PCB, such as a right angle. The closer the patch is to the meander, smaller patches can be used.  
         [0020]    [0020]FIG. 3 shows another combination meanderline antenna  300 . Meanderline antenna  300  includes the identical elements to meanderline antenna  200 , but also includes patch element feed  302 . Patch element feed  302  provides conductive path to patch element  202 . Patch feed element  302  is shown as a continuation or extension of patch element  202 , but could be any conventional material capable of conducting power to patch element  202  including without limitation a power feed, and/or a coherent power source (not shown) separate from lead  106 . Providing power to patch element  202  may result in power vs frequency plot as shown in FIG. 5. As shown in FIG. 5, supplying power to patch element  202  increases the usable bandwidth of the antenna. Patch element feed  302  is shown connected to lead  106 , however, patch element feed  302  could be separately connected to a coherent power source (not shown).  
         [0021]    On reading the disclosure, one of skill in the art will now recognize that a patch element, such as patch element  202 , couple be attached to a conventional meanderline antenna. For example, meanderline antenna  100  could be improved by adding a patch element to the antenna. The patch element could be etched into a printed circuit board, for example, and attached to antenna  100  using any conventional means to provide the combination meanderline, patch antenna. Such conventional means to attach the meander antenna to a PCB could be to solder to patch feed  302 , screws or bolts to attach a patch element above antenna  100  (not shown), friction fittings, snap locks, or the like.  
         [0022]    While the invention has been particularly shown and described with reference to an embodiment thereof, it will be understood by those skilled in the art that various other changes in the form and details may be made without departing from the spirit and scope of the invention.