Shorting Pins Application in Wide-Band E-Shaped Patch Antenna

Table 1 presents frequency values after the pin insertion atdifferent positions. The Fig. 4 shows the values when pinposition is Yp=27mm and feeding position Yo=25mm.Table 1 – Lower and higher resonant frequenciesYo(mm)Yp(mm)Lowerfrequency(GHz)Higherfrequency(GHz)43.5 45.0 0.71 1.8137.0 39.0 0.72 1.8032.0 33.0 0.71 1.8025.0 27.0 0.70 2.0619.5 21.0 0.66 2.30According to Table 1, two resonant frequencies appearwhen a pin is positioned close to the feeding position, eachone with relative bandwidth of 3%. This is very adequate toapplications where two carriers are necessary. To achievewideband antenna, it is necessary to modify the feed and pinpositions. As the lower resonant frequency obtained for F2 is1.8 GHz, the pin position Yp=33m is chosen. It is importantto remember that the lower frequency means bigger sizereduction. To obtain the feeding position, experiments arenecessary to determine where the antenna input impedance ismatched to its feeding structure.B. Full E antenna with pin, showing smaller dimensions thanE reference antennaThe dimensions, parameters and results for three Eformat antennas of reduced dimension with position pinYp=33mm, thickness h=10mm and air dielectric are on Table2 and 3. The area reduction is relative to the referenceantenna from Fig. 2, of area 31.5 cm 2 .Table 2 – Antenna dimensions for pin position Yp=33mm13.0 15.0 0.61 2.37AntennaLWWsPsLsYo8.0 9.0 0.57 2.96(mm)(mm)(mm)(mm)(mm)(mm)1.0 3.0 0.54 3.00A 40 35 5 6 31 12B 40 40 5 6 34 11C 50 40 5 6 34 1010S11 (dB)0-10-20-30-400.5 1 1.5 2 2.5 3Frequency (GHz)Fig. 4 - E shape antenna with pin and doubleresonance (0.70 and 2.06 GHz), for Yo=25mmand Yp=27 mm.Table 3 – Antenna results for pin position Yp=33mmAntennaBW(%)BW(MHz)Areareduction(%)A 10 260 55B 13 350 50C 16 440 37The antennas A, B and C show increase in its lowerfrequency due pin to the application and lower Ls parameter.The bandwidth is also decreased because it has lower volume,according to equations (1) and (2). The simulated bandwidthvalues, center frequency and return loss for the three antennasare shown in Fig. 5. The Fig. 5 also shows measured valuefor antenna C.2009 SBMO/IEEE MTT-S International Microwave & Optoelectronics Conference (IMOC 2009) 231

YoYoC). The goal is to find the pin position where the higherresonant frequency has greater reduction.S11 (dB)0-5-10-15-20Antenna A (predicted)-25 Antenna B (predicted)Antenna C (predicted)Antenna C (measured)-302 2.2 2.4 2.6 2.8 3Frequency (GHz)Fig. 5– Return losses for the reduced size E antenna withthe pin position Yp=33mm and for three antennas: BW260 MHz (antenna A), 350 MHz (antenna B) and 440MHz (antenna C).C. Half E antenna, with pinSimilar to the process employed to a full E antennadescribed on item B, a pin will be applied to the half Eantenna with dimensions L=35mm, W=45mm, Ls=35mm,Ps=6mm and Ws=4mm, with h=10mm and air dielectric(Fig.6).L- Region ATable 4 presents values and results for the pin in the RegionA. The Fig.7 shows the geometry and Fig.8 is an examplewhen Yp=15mm and Yo=13mm Since the antenna isasymmetrical, three resonant frequencies (F1, F2 and F3) arepresent, where the major reduction of F3 (higher frequency)will indicate the position to apply the pin to minimize size ofthe antenna (Yp=32mm or 13 mm from the back border).Table 4 – Resonant frequencies in Region AYo Yp F1 F2 F3(mm) (mm) (GHz) (GHz) (GHz)43.0 44.0 0.91 1.85 2.8437.0 38.0 0.86 1.79 2.8131.0 32.0 0.84 1.90 2.6425.0 27.0 0.82 2.11 2.6419.0 20.0 0.77 2.30 2.6413.0 15.0 0.71 2.34 2.946.0 7.0 0.67 2.28 3.001.0 2.0 0.62 2.23 3.00Region ARegion BYpYLFeedWXPinYoLsRegion CFeedWPsWsFig.6– Patch geometry, with three regions forthe pin application.L=35 mm and W=45 mm, Region A.The step one, since it is a non symmetrical antenna, willbe to verify which region has the more appropriatebandwidth. These regions are located on the left border(Region A), back border (Region B) and right border (RegionYpPsYoWsFig.7– Half E antenna with the pin anddimensions L=35 mm and W=45 mm, Region A.Ls2009 SBMO/IEEE MTT-S International Microwave & Optoelectronics Conference (IMOC 2009) 232

YoL20-2YpYoS11(dB)-4-6-8-10FeedPinW-12-14-16Ls-180.5 1 1.5 2 2.5 3 3.5Frequency (GHz)Fig.8– Example of the half E antenna with pinand triple resonance (0.71, 2.34 and 2.94 GHz),for Yo=13mm and Yp=15 mm.The same process occur with Regions B (Fig.9) and C(Fig.10), where the major reduction of F3 (higher frequency)indicate the position to apply the pin to minimize size(Yp=34mm or 1mm from the back border to Region B andYp=14mm or 14mm from the back border to Region C).Tables 5 and 6 present respectively resonant frequencies forRegion B and C.- Region BTable 5 – Resonant frequencies in Region BYo Yp F1 F2 F3(mm) (mm) (GHz) (GHz) (GHz)2.0 1.0 0.81 1.74 2.862.0 7.0 0.86 1.72 2.901.5 13.0 0.90 1.71 2.962.0 19.0 0.92 1.71 3.002.0 26.0 0.89 1.71 2.981.5 31.0 0.85 1.71 2.882.0 34.0 0.82 1.73 2.85Ps WsFig.9– Half E antenna with pin and dimensionsL=35 mm and W=45 mm, Region B.- Region CTable 6 – Resonant frequencies in Region CYo Yp Freq.1 Freq.2 Freq.3(mm) (mm) (GHz) (GHz) (GHz)2.0 1.0 0.85 1.73 2.858.5 7.0 0.89 1.75 2.7615.5 14.0 0.92 1.79 2.7620.5 19.0 0.93 1.84 2.7627.0 25.0 0.92 1.88 2.7632.5 31.0 0.89 1.91 2.7939.0 37.0 0.85 1.91 2.9145.0 43.0 0.84 1.92 2.95When the pin positions for the three Regions areobtained, the resulting dimensions of the half E antennasafter simulations are: Region A (L=30mm, W=40mm,Ls=31mm, Ws=6mm, Ps=5mm, Yp=27mm, Yo=16 mm eh=10 mm); Region B (L=30mm, W=40mm, Ls=31mm,Ws=6mm, Ps=4mm, Yp=29mm, Yo=11mm e h=10 mm);Region C (L=30mm, W=40mm, Ls=31mm, Ws=6 mm, Ps=4mm, Yp=14mm, Yo=15 mm e h=10 mm). The feedingposition Yo, shown on Fig. 6, is the same for all Regions.2009 SBMO/IEEE MTT-S International Microwave & Optoelectronics Conference (IMOC 2009) 233