Abstract:
A Planar Inverted-F Wing Antenna (PIFWA) device, system, and method used for commercial and residential induction cooking tops, ovens, combo-steamers, and pressure cookers. The outline of the PIFWA is an isosceles triangle with a truncated vertex end opposite the base side. The PIFWA transmits and receives (TX/RX) signals with wireless sensors including Surface Acoustic Wave (SAW) devices. The antenna comprises a device, system, and method to monitor the cooking process and temperature of food. Embodiments of the PIFWA antenna operate at about 433 MHz, have a feed between two slots, and a shorting plate at the opposing end. Antenna location and alignment within the culinary appliance provides uniform signal strength and gain performance in the regions occupied by one or more sensors.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of PCT Application No. PCT/US2014/037313 filed 8 May 2014 which claims the benefit of U.S. Provisional Application No. 61/821,414 filed 9 May 2013 . Each of these applications is herein incorporated by reference in their entirety for all purposes. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a Planar Inverted-F Wing Antenna (PIFWA) used in commercial and residential induction cooking tops, ovens, combo-steamers and pressure cookers. The PIFWA is used to transmit and receive (TX/RX) signals with a wireless Surface Acoustic Wave (SAW) or other sensor. The device, system, and method are used to monitor the cooking process and temperature of the food. Embodiments of the PIFWA antenna are configured for use with a surface acoustic wave (SAW) device for wireless temperature sensing. 
       BACKGROUND OF THE INVENTION 
       [0003]    Cooking unit parameter measurement (such as temperature measurement) is a difficult environment. For example, significant heat is present, there are sanitary requirements, and there are important safety demands. Reliable, accurate, and convenient operation is needed. Wired probes exist, but they are not convenient; the cables can be damaged or cut. Wireless probe systems can be complex, expensive, and unreliable. The transmit/receive frequencies employed interact with the metals of appliances to make reliable measurement very difficult. Where antenna signal strength patterns are not smooth, but notched, the link budget for probes can be too restrictive for reliable, accurate, operation. A probe placed in a low signal strength area proximate an appliance may fail to provide any signal. Considerations include power flux density, field strength, phase, polarization, and near-field effects. Missing probe signals can produce erroneous measurement values, leading to poor cooking results. Poor cooking, such as undercooking, can lead to serious illness. 
         [0004]    Antennas, the ground plane environment, and materials must all be considered to produce results acceptable for wireless operation. The ground plane of the antenna plays a significant role in its operation. For example, if the ground plane is much larger than λ/2, radiation patterns will become increasingly multilobed. Alternatively, if the ground plane is significantly smaller than λ/2, tuning becomes increasingly difficult, and overall performance degrades. Additionally, ground surface waves can produce spurious radiation, or couple energy at discontinuities, leading to distortions in the main pattern, or unwanted loss of power. 
         [0005]    What is needed is an antenna device and wireless transmit/receive system for communication between at least one wireless sensor and a culinary appliance to monitor the cooking process including temperature of food that provides uniform signal strength and gain performance in the near-field regions occupied by the sensor(s). 
       SUMMARY OF THE INVENTION 
       [0006]    An embodiment provides a Planar Inverted-F Wing Antenna (PIFWA) device comprising a feed end; a shorting end opposite the feed end; a feed section between a first slot and a second slot; a first wing section on a side of the first slot opposite the feed section; a second wing section on a side of the second slot opposite the feed section; wherein the outline configuration of the PIFWA in the plane of the PIFWA is an isosceles triangle with a truncated vertex end opposite the base side; the PIFWA device located proximate a culinary appliance. In embodiments the culinary appliance is a cooktop. In other embodiments, the culinary appliance is an induction cooktop. In subsequent embodiments a feed side of the PIFWA is aligned perpendicular to an adjacent side of a cooktop, located proximate a corner of the cooktop. For additional embodiments the operating frequency of the PIFWA is about 433 MHz. In another embodiment, the PIFWA has an impedance bandwidth of least about 13 MHz. In included embodiments the PIFWA has a maximum gain of about 3.6 dB. In yet further embodiments the culinary appliance is an oven, a pressure cooker, or a combo-steamer. Embodiments further provide that the PIFWA communicates with a surface acoustic wave (SAW) sensor. For a following embodiment the PIFWA communicates with a surface acoustic wave (SAW) sensor and values of measurements made by the sensor are used to control the power of the culinary appliance. In subsequent embodiments the PIFWA is located within a cooktop, the location comprising a shorting edge of the shorting end, the shorting edge parallel to and separated from a first inner side of the cooktop by about 76.8 mm measured perpendicular to the shorting edge; a corner of the first wing, the corner of the first wing proximate a second inner side of the cooktop, the corner of the first wing separated from the second inner side of the cooktop by about 8.8 mm. In additional embodiments the PIFWA dimensions comprise a shorting edge width approximately equal to a slot length; an overall length approximately equal to an overall width; a slot width approximately equal to one fifth of a wing end width; and a feed leg width approximately one third of the slot width. In included embodiments the PIFWA dimensions comprise an overall length of about 118 mm; an overall width of about 118 mm; a wing width of about 47.5 mm; a wing outer edge length of about 122.8 mm; a feed leg width of about 3 mm; slot widths of about 10 mm each; a slot length of about 55 mm; and an overall height of about 15.3 mm. 
         [0007]    Another embodiment provides a method for measuring physical parameter values with a culinary appliance comprising the steps of providing at least one Planar Inverted-F Wing Antenna (PIFWA) proximate the culinary appliance; wherein the outline configuration of the PIFWA in the plane of the PIFWA is an isosceles triangle with a truncated vertex end opposite the base side; transmitting at least one RF signal from the at least one PIFWA; receiving at at least one wireless sensor, the RF signal transmitted from the PIFWA; radiating from the at least one wireless sensor, at least one RF signal; receiving, at the at least one PIFWA, the radiated signal from the at least one wireless sensor; the at least one RF signal transmitted from the at least one PIFWA and the at least one RF signal radiated from the at least one wireless sensor corresponding to the measured physical parameter values. In related embodiments at least one wireless sensor is a surface acoustic wave (SAW) sensor. For further embodiments at least one surface acoustic wave (SAW) sensor is a temperature sensor. In ensuing embodiments, the culinary appliance is a cooktop. In yet further embodiments at least one wireless sensor is a surface acoustic wave (SAW) temperature probe. 
         [0008]    A yet further embodiment provides a system for measuring physical parameter values with a culinary appliance with a Planar Inverted-F Wing Antenna (PIFWA) comprising a PIFWA feed end; a PIFWA shorting end opposite the feed end; a PIFWA feed section between a first slot and a second slot, the feed section extending beyond the line of the base side; a PIFWA first wing section on a side of the first slot opposite the feed section; a PIFWA second wing section on a side of the second slot opposite the feed section, wherein the outline configuration of the PIFWA in the plane of the PIFWA is an isosceles triangle with a truncated vertex end opposite the base side; the PIFWA located proximate a culinary appliance; and the PIFWA providing RF communication with a surface acoustic wave (SAW) sensor whereby values of measurements made by the sensor are used to control power of the culinary appliance. 
         [0009]    The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  depicts simplified culinary appliance application environments for an embodiment of the present invention. 
           [0011]      FIG. 2  depicts a simplified Planar Inverted-F Wing Antenna (PIFWA) cook top application layout for an embodiment of the present invention. 
           [0012]      FIG. 3  depicts a planar wing-shaped antenna for an embodiment of the present invention. 
           [0013]      FIG. 4  is a planar wing-shaped antenna embodiment for air-filled free space modeling configured in accordance with the present invention. 
           [0014]      FIG. 5  is a planar wing-shaped antenna air-filled free space reflection coefficient plot configured in accordance with the present invention. 
           [0015]      FIG. 6  is a planar wing-shaped antenna air-filled free space gain plot configured in accordance with the present invention. 
           [0016]      FIG. 7  depicts a scale drawing for corner placement of a planar wing-shaped antenna embodiment configured in accordance with the present invention. 
           [0017]      FIG. 8  is a reflection coefficient plot for the  FIG. 7  corner placement of a planar wing-shaped antenna configured in accordance with the present invention. 
           [0018]      FIG. 9  depicts a first set of four examples of corner placements of planar wing-shaped antenna embodiments configured in accordance with the present invention. 
           [0019]      FIG. 10  depicts a second set of four examples of corner placements of planar wing-shaped antenna embodiments configured in accordance with the present invention. 
           [0020]      FIG. 11  depicts a third set of four examples of corner placements of planar wing-shaped antenna embodiments configured in accordance with the present invention. 
           [0021]      FIG. 12  is an S(1, 1) plot of planar wing-shaped antenna embodiments configured in accordance with the present invention. 
           [0022]      FIG. 13  is an S(1, 1) plot of planar wing-shaped antenna embodiment  11 D configured in accordance with the present invention. 
           [0023]      FIG. 14  is a radiation pattern plot of planar wing-shaped antenna configuration  11 D. 
           [0024]      FIG. 15  depicts a perspective view of a cooktop with a narrow-feed PIFWA embodiment configured in accordance with the present invention. 
           [0025]      FIG. 16  depicts a scale trimetric perspective view of a section of a cooktop showing a narrow-feed PIFWA embodiment configured in accordance with the present invention. 
           [0026]      FIG. 17  depicts a scale plan view of a cooktop with a narrow-feed PIFWA embodiment configured in accordance with the present invention. 
           [0027]      FIG. 18  depicts scale views of a narrow-feed PIFWA embodiment configured in accordance with the present invention. 
           [0028]      FIG. 19  is a reflection coefficient impedance bandwidth plot for the narrow-feed PIFWA embodiment in a cooktop of  FIGS. 15-18  configured in accordance with the present invention. 
           [0029]      FIG. 20  is a broadside gain plot for the narrow-feed PIFWA embodiment in a cooktop of  FIGS. 15-18  configured in accordance with the present invention. 
           [0030]      FIG. 21  depicts broadside gain in three dimensions, trimetric view for the narrow-feed PIFWA embodiment in a cooktop of  FIGS. 15-18  configured in accordance with the present invention. 
           [0031]      FIG. 22  depicts broadside gain bottom view for the narrow-feed PIFWA embodiment in a cooktop of  FIGS. 15-18  configured in accordance with the present invention. 
           [0032]      FIG. 23  depicts broadside gain top view for the narrow-feed PIFWA embodiment in a cooktop of  FIGS. 15-18  configured in accordance with the present invention. 
           [0033]      FIG. 24  depicts a method of use of a cooktop with a PIFWA configured in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    PIFWA antenna system embodiments have an advantage in that the ground plane of the antenna plays a significant role in its operation. By using the appliance&#39;s metal walls or body as the antenna ground plane (which is much longer than λ/2 for 433 MHz), the radiation patterns become increasingly multi lobed. Embodiments exhibit omni radiation patterns. 
         [0035]    Additionally, for embodiments, the antenna is low cost and easy to assemble in the culinary appliances; it has a relatively high gain and suitable radiation pattern for ovens and cooking top/hop applications; up to a 15% bandwidth is possible. 
         [0036]    Embodiment applications comprise culinary appliances such as cooking hops (tops), cooking ovens, combo-steamers, and pressure cookers. 
         [0037]    In embodiments, nonlimiting shapes for the antenna comprise: round, wing design as for a cooking top, rectangular, and triangular. Other shapes are possible. 
         [0038]    GLOSSARY To assist in understanding, terminology is initially defined. 
         [0039]    Antenna shorting edge width is the width of the antenna side opposite the feed side of a PIFWA. 
         [0040]    Coaxial cable feed is the input connection to the feed slot of a PIFWA. 
         [0041]    Feed width is the width of the feed leg between the two slots of a PIFWA. 
         [0042]    Inverted-F Antenna (IFA) has the feed placed from the ground plane to the upper arm of the IFA. The upper arm of the IFA has a length approximately a quarter wavelength. Beside the feed, the upper arm is shorted to the ground plane. The feed is closer to the shorting pin than to the open end of the upper arm. The structure somewhat resembles an Inverted-F. 
         [0043]    Near-field is the region within one wavelength of the transmit point. 
         [0044]    Planar Inverted-F Antenna (PIFA) is a variant of a linear inverted-F antenna with the wire radiator element replaced by a plate. The PIFA is resonant at a quarter-wavelength due to the shorting pin at the end. The feed is placed between the open and shorted end. In PIFAs, the shorting pin can be a plate. 
         [0045]    Slot length is the distance from end of the adjacent wing to the enclosed end of the slot of a PIFWA. 
         [0046]    Slot width is the distance between the side edge of the feed leg and the adjacent wing edge of a PIFWA. 
         [0047]    Wing width is the width of the independent end of the identified wing of a PIFWA opposite the shorting end. 
         [0048]      FIG. 1  depicts simplified planar Inverted-F Wing Antenna (PIFWA) culinary appliance application environments  100  for embodiments of the present invention. For a cooktop, PIFWA  105  communicates with wireless food probe  110 ; induction pot (magnetic)  115  is on ceramic-glass top plate  120 ; beneath is induction coil  125 ; fed by electrical power source  130 . Electronics  135  interface with antenna  105 . For measurements, diameter of pot  115  (with water) was 175 mm and the antenna of probe  110  was 95 mm over the glass of the cook top. Additional culinary appliances include oven  140 , pressure cooker  145 , and combo-steamer  150 . 
         [0049]      FIG. 2  depicts a simplified plan view  200  of an induction cook top layout. Nonlimiting PIFWA antenna locations  205  are shown with induction coil example locations  210  on cooktop  215 . 
         [0050]      FIG. 3  depicts a planar wing-shaped antenna  300 . Components comprise first wing  305 ; second wing  310 , feed  315 ; slots  320 ; and coaxial cable feed  325 . Dimension nomenclature includes overall width  330 ; overall length  335 ; wing outer edge length  340 ; antenna shorting edge width  345 ; first wing width  350 ; second wing width  355 ; feed width  360 ; slot length  365 ; and slot width  370 . The outline of the antenna in the plane of the antenna is an isosceles triangle with a truncated vertex at the shorting edge end, having shorting edge width  345  opposite the base side having overall width  330 . For embodiments, each symmetric wing has a right triangle outline in the plane of the antenna with a truncated vertex along the altitude, opposite the base side having overall width  305 ,  310 . In embodiments, feed  315  extends beyond line of base side having overall width  330 . 
         [0051]      FIG. 4  depicts views of a planar wing-shape antenna embodiment  400  shown in  FIG. 3 . Included in views are plan projection  405 ; side projection  410  showing feed line  415 . Views are to scale and slots  420  are narrower (and feed wider) than those of the embodiment of  FIG. 7 . A computer model of this embodiment provides the data for the free-space performance parameters depicted in  FIGS. 5 and 6 . 
         [0052]      FIG. 5  depicts air-filled free space dB(S(1, 1)) reflection coefficient sweep setup plot  500  for the planar wing-shape antenna embodiment of  FIG. 4 . Curve  505  includes point ml  510  with values of 433.0000 MHz and −30.4230 dB. The curve&#39;s −10 dB points are from 422.5500 MHz  515  to 443.4500 MHz  520 , a 20.900 MHz band  525 . Point  530  value at 422.5500 MHz is −10.0851 dB. Point  535  value at 443.4500 MHz is −10.0101 dB. 
         [0053]      FIG. 6  depicts air-filled free space gain plot in dB  600  for the planar wing-shape antenna embodiment of  FIG. 4 . Upper plot is total gain plot  6 A and lower plot is vertical polarization gain  6 B, in dB. 
         [0054]      FIG. 7  depicts a first modeled PIFWA embodiment in a cook top with corner placement  700 . Various results show that the presence of the large metal coils in the cooktop has a severe effect on the performance of the PIFWA. The surrounding metal cooktop lip also has a negative impact. 
         [0055]      FIG. 8  is a reflection coefficient plot  800  for another modeled PIFWA embodiment showing adequate bandwidth, depicting tuning to about 433 MHz. Curve  805  includes point ml  810  with values of 430 MHz and −33 dB. The curve&#39;s −10 dB points are from 423.1390 MHz  815  to 444.8430 MHz  820 , a 21.7040 MHz band  825 . Point  830  value at 423.1390 MHz is −9.9317 dB. Point  835  value at 444.8430 MHz is −9.7187 dB. 
         [0056]      FIG. 9  depicts a first set of four to-scale antenna embodiments and placements  900 . Embodiment  9 A is tuned to the desired 433 MHz center frequency comprising an elongated main body of the PIFWA with an expanded width of the transmission line, increasing antenna bandwidth. Embodiment  9 B depicts the feed aligned with one of the cooktop walls. This accommodates antenna shape while keeping the feed from the heating elements. Embodiment  9 C depicts the feed aligned with another one of the cooktop walls. This also accommodates the antenna shape while keeping the feed away from the heating elements. Embodiment  9 D depicts the feed mounted at an angle relative to the edges. This accommodates the antenna shape while keeping the feed away from the heating elements. For embodiments, angle may vary while maintaining performance. 
         [0057]      FIG. 10  depicts a second set of four to-scale antenna embodiments and placements  1000 . Embodiment  10 A has the feed side parallel to the cooktop edge, with similar, equilateral, triangular side lengths, and slots of average width and separation. Embodiment  10 B also has the feed side parallel to the cooktop edge, similar isosceles triangular side lengths with the (feed) base longer than the sides, and slots of average width and separation. Embodiment  10 C similarly has the feed side parallel to the cooktop edge with a rectangular wing configuration and slots of average width and separation. Embodiment  10 D depicts the feed side parallel to the cooktop edge, similar isosceles triangular side lengths with the (feed) base longer than the sides, and slots of average width with a separation approximately three times slot width. 
         [0058]      FIG. 11  depicts a third set of four to-scale antenna embodiments and placements  1100 . Embodiment  11 A has the feed side parallel to the cooktop edge, similar isosceles triangular side lengths with the (feed) base longer than the sides, and wide slots each approximately one-quarter the base length, with a separation of approximately one-quarter the slot width. Embodiment  11 B has the feed side parallel to the cooktop edge, similar isosceles triangular side lengths with the (feed) base shorter than the sides, and slots of narrow width with a separation approximately twice one slot width. Embodiment  11 C has the feed side parallel to the cooktop edge, a rectangular outline, side length approximately two to one with the (feed) base one of the shorter sides, and slots of narrow width with a separation approximately twice one slot width. Embodiment  11 D has the feed side parallel to cooktop edge, a generally square outline, and slots of narrow width with a separation approximately twice one slot width. 
         [0059]      FIG. 12  is an S(1, 1) plot  1200  of curves 1-4 ( 10 A- 10 D, respectively) in dB depicting the presence of the large metal coils and the lip of the cooktop surrounding the antenna; results are highly localized. Deep resonances in the reflection coefficient exist, and slight changes in antenna configuration produce vastly different results. Examples of this are evident in the four curves plotted. Other embodiments include variations on both a rectangular PIFWA and simple transmission line antenna (no short at the end). Antenna height was examined to determine if any benefits could be achieved by physically decoupling the antenna surface from the lossy glass top. Generally, for embodiments, less desirable results were found, so antenna height has been kept constant for embodiments, coincident with the bottom of the glass. 
         [0060]      FIG. 13  is an S(1, 1) plot  1300  in dB for antenna embodiment  11 D. Curve  1305  includes point ml  1310  with values of 440 MHz and −27.3585 dB. The curve&#39;s −10 dB points are from 427.1000 MHz  1315  to 452.7000 MHz  1320 , a 25.600 MHz band  1325 . Point  1330  value at 452.7000 MHz is −10.0064 dB. Point  1335  value at 443.4500 MHz is −10.0505 dB. A significant minimum exists at 440 MHz, providing sufficient bandwidth. Dimensions are: a=90 mm, length=110 mm, slot length=82 mm, slot width=1 mm, and t 1  width=2 mm. 
         [0061]      FIG. 14  is radiation pattern  1400  in dB (total gain) of interim result antenna configuration  11 D. 
         [0062]    Other embodiments include variations on both a rectangular PIFWA and simple transmission line antenna (no short at the end). Antenna height was examined to determine if any benefits could be achieved by physically decoupling the antenna surface from the lossy glass top. Generally, for embodiments, less desirable results were found, so antenna height has been kept constant for embodiments, coincident with the bottom of the glass. 
         [0063]      FIG. 15  is a perspective scale-view of a cooktop with a narrow-feed PIFWA embodiment  1500  operating at 433 MHz. Cooktop includes corner-mounted, narrow-feed, PIFWA  1505  and cooking elements  1510 . Embodiment designs comprised taking a free-space Planar Inverted-F-Antenna (PIFWA) assembly operating at 433 MHz and adapting it to the environment of an induction cooktop. An original PIFWA design conceived for stand-alone, open air applications and functioned well in free-space. Modifications to the original PIFWA design conceived for stand-alone, open air application were required by embodiments to accommodate the new cooktop environment. 
         [0064]      FIG. 16  is a scale perspective view of the narrow-feed PIFWA embodiment antenna location  1600  determined with respect to the locations of induction coils, electronics, and pockets of empty space within the cooktop, and the size of the antenna. Cooktop includes corner-mounted, narrow-feed, PIFWA  1605  and cooking elements  1610 . Two related embodiment locations are presented. These two locations, which are mirror images of each other, are the corner pockets of space formed between the cooktop undercarriage lip and two of the four induction coils. The antenna is fed through the thin microstrip traversing down the center of the geometry. This antenna embodiment has shorter overall length and width dimensions that the modeled free-space embodiment. The feeding microstrip is also significantly thinner. 
         [0065]      FIG. 17  is a scale plan view of the cooktop narrow-feed PIFWA embodiment  1700  showing dimensions within the cooktop. Cooktop includes corner-mounted, narrow-feed, PIFWA  1705  and cooking elements  1710 . 
         [0066]      FIG. 18  depicts orthogonal scale views of the cooktop narrow-feed PIFWA embodiment  1800  (also shown in  FIG. 17 ) showing antenna dimensions. Orthogonal views include plan  1805 , side  1810 , and end  1815 . Embodiments are made out of tinned metal. For embodiments, the antenna cable is soldered on the tip of the antenna, and the ground is connected to the cook top case. For embodiment tests the PIFWA was inside the induction cook top. Approximate embodiment dimensions comprise a shorting edge width approximately equal to the slot length. Overall length approximately equals overall width. Slot width approximately equals one fifth wing end width, and feed width is approximately one third slot width. 
         [0067]      FIG. 19  is a reflection coefficient and impedance bandwidth graph  1900  of the reflection coefficient for the narrow-feed PIFWA embodiment of  FIGS. 15-18 . Curve  1905  includes point ml  1910  with values of 434.0000 MHz and −20.3370 dB. The curve&#39;s −10 dB points are from 427.3585 MHz  1915  to 440.7233 MHz  1920 , a 13.3648 MHz band  1925 . Point  1930  value at 427.3585 MHz is −10.0954 dB. Point  1935  value at 440.7233 MHz is −10.0049 dB. It has a minimum value of −20 dB at 434 MHz, very close to the desired operating frequency of 433 MHz. As can be seen in the figure, an impedance bandwidth of approximately 13.4 MHz is obtained by using the narrow-feed PIFWA embodiment configuration depicted in  FIGS. 15-18 . This is outstanding performance resulting from the particular values for the many variables disclosed for this embodiment and the considerations involved. 
         [0068]      FIG. 20  is a broadside radiation pattern gain  2000  for the cooktop narrow-feed PIFWA embodiment operating at 433 MHz seen in two dimensions. A peak gain value of 3.6 dB is found at the apex of the pattern. Moving 60 degrees to the left and right of this peak produce broadside gain values of 0.8 dB and −0.4 dB, respectively. The shape of the pattern is affected by the presence of the induction coils. For example, a small backside lobe is present in the pattern. Additionally, the pattern is comprised primarily of one large frontal lobe, similar to a monopole antenna. These attributes are in contrast to the pattern produced by the previous designs, which had no backside lobe and looked essentially like the radiation pattern of a dipole with a null point at the center. As with the plot of  FIG. 19 , this is outstanding performance resulting from the particular values for the many variables disclosed for this embodiment and the considerations involved. 
         [0069]      FIG. 21  is a radiation pattern gain  2100  in three dimensions for the cooktop narrow-feed PIFWA embodiment operating at 433 MHz, trimetric view. 
         [0070]      FIG. 22  is a bottom view radiation pattern gain  2200  in three dimensions for the cooktop narrow-feed PIFWA embodiment operating at 433 MHz. 
         [0071]      FIG. 23  is a top view radiation pattern gain  2300  in three dimensions for cooktop narrow-feed PIFWA embodiment operating at 433 MHz. The beginnings of the formulation of a null seem to be starting, but this is much more subtle than in the traditional PIFWA pattern. As mentioned above, the radiation pattern of the antenna is unorthodox with respect to the general PIFWA topology. For embodiments, modifying the pattern is accomplished by increasing the antenna width at the base or including various parasitically excited objects either along the feed line or at the edges of the base. For some embodiments, a 3 mm separation distance between the antenna and coils must be maintained. In embodiments, parasitically excited monopoles realized with one or more screws attached to the cooktop base are placed along the microstrip feed to help shape the pattern into a more traditional shape. For embodiments, simpler designs (i.e., rectangular and circular microstrips, etc.) are used; dimension restrictions give considerations for these configurations. 
         [0072]      FIG. 24  is a method of use flow chart  2400  for PIFWA embodiments. Steps comprise providing a cooktop comprising a PIFWA  2405 ; providing a Surface Acoustic Wave (SAW) probe  2410  for measuring cooking subject matter; initiating cooking  2415 ; transmitting from the PIFWA to the probe  2420 ; receiving a SAW signal at the PIFWA from the probe corresponding to a measurement  2425 ; decoding the measurement value from the SAW signal received at the PIFWA  2430 ; and responding to value by providing indication of influence of value on the cooking subject matter  2435  (such as doneness). 
         [0073]    The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. Each and every page of this submission, and all contents thereon, however characterized, identified, or numbered, is considered a substantive part of this application for all purposes, irrespective of form or placement within the application. This specification is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure.