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TABLE 9: 4-X-5 ELEMENT LINEAR ARRAY WITH AZIMUTH AMPLITUDE TAPER a. 4-x-5 Linear Array with Azimuth Amplitude Taper Each row of the array is fed from the output of an equal amplitude power divider. As a result, each of the 1-x-5 composite arrays has an equal distribution in elevation. b. Conductor Current Distribution The conductor current discloses near zero phase excitation. Note the slight advance of the phase excitation at the first element. The non- zero phase excitation contributes to pattern asymmetry. c. 4-x-5 Array Radiation Patterns The lower sidelobe levels of the azimuth pattern (red) disclose the amplitude taper. The asymmetry of the azimuth pattern reflects the minor, non-zero phase excitation as evident from the conductor current. The expected gain increase of 6.0 dB over the 1-x-5 array is not realized due to power divider and conductor losses. d. 4-x-5 Array Input Impedance The 4-x-5 array input impedance appears well matched; the result of optimization of the 1-x-5 prior to elevation expansion of the array. The bandwidth of the matched impedance may be improved by adjusting the center frequency impedance point to the right in the 1_x-5 array. The input impedance at the band edges is improved with only a slight degradation to the center frequency impedance. As a final example of microstrip antenna array properties, the previous 4-x-5 array performance is enhanced by amplitude taper in elevation to reduce the elevation beam sidelobes. The results are graphically illustrated in Table 10. 1 0 -10 -20 -30 -40 -50 -60 -70 -80 - 9 0 -100 -110 -120 -130 -140 -150 -160 -170 180 170 160 150 140 130 120 110 100 9 0 80 70 60 50 40 30 20 10 Azimuth and Elevation Patterns Mag Max 20 dB Mag Min -30 dB 10 dB Per Div p2 p1 Mag 18.38 Ang 0 DB(|PPC_EPhi(0,1,90,2,1)|)[1] 4_x_5_SF_Array_A.$FSAMP DB(|PPC_ETheta(0,1,0,2,1)|)[1] 4_x_5_SF_Array_A.$FSAMP p1: FREQ = 5.8 GHz p2: FREQ = 5.8 GHz 0 1.0 1.0 -1.0 10.0 10.0 -10.0 5.0 5.0 -5.0 2.0 2.0 -2.0 3.0 3.0 -3.0 4.0 4.0 -4.0 0.2 0.2 -0.2 0.4 0.4 -0.4 0.6 0.6 -0.6 0.8 0.8 -0.8 Input Impedance Swp Max 5.9GHz Swp Min 5.7GHz 5.8 GHz r 0.848633 x -0.0316375 S(1,1) 4_x_5_SF_Array_A Microstrip Antenna Design 22 www.cadence.com/go/awr

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