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TABLE 10: 4-X-5 ELEMENT LINEAR ARRAY WITH AZIMUTH AND ELEVATION AMPLITUDE TAPER a. 4-x-5 Linear Array with Azimuth and Elevation Amplitude Taper Each row of the array is fed from the output of an unequal amplitude power divider. As a result, the amplitude has an unequal distribution in elevation. b. Conductor Current Distribution The conductor current discloses near zero phase excitation. Note the reduced conductor current of the top and bottom rows of the array. c. 4-x-5 Array Radiation Patterns The lower sidelobe levels of both patterns reflect the two dimensional amplitude taper. The gain is slightly reduced from the equal power distribution of the previous array. In many applications, -20 dB sideband levels are acceptable. 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 array 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. Notwithstanding the flexibility and ease of incremental design and analysis, the series/parallel feed of microstrip array antennas is limited; particularly with respect to amplitude taper of the series feed elements. The limitation in magnitude of the amplitude distribution results directly from the limited sensitivity of the single element microstrip antenna to variation in conductor width, W. A quantitative evaluation of the sensitivity of microstrip antenna directivity may be attained via numeric evaluation of the single element directivity equation (equation 12) with W as a variable. 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 18.16 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 1.07574 x -0.0849199 S(1,1) 4_x_5_SF_Array_A Microstrip Antenna Design 23 www.cadence.com/go/awr

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