AWR eBooks

The differential feed at the center of the conductor pattern may be implemented from a balun located below the plane of the array. Differential feed is required in this case due to the inverse polarity of the radiating edges. The input impedance is 100 Ohms at the center frequency which is commensurate with typical balun impedance. TABLE 7: PERFORMANCE OF TWO-X-TWO MICROSTRIP ANTENNA ARRAY Two x Two Array Conductor Pattern Two x Two Array Conductor Current (note equal phase and amplitude excitation) Two x Two Array Radiation Patterns Two x Two Array input impedance The individual excitation parameters of amplitude and phase determine the principal radiation intensity beamwidth, gain, direction and sidelobe level. Clearly, antenna arrays are significant performance determinants to communication and radar systems. SERIES FEED FOR MICROSTRIP ARRAY ANTENNAS 22 In addition to the parallel, or corporate, feed for microstrip antenna arrays, the series feed offers an additional method of array implementation. The microstrip array series feed is illustrated in Figure 11 where an N-element 22 The series fed array is also referred to as a traveling wave antenna. 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 11.45 Ang 0 DB(| PPC_EPhi(0,1,90,2,1)| )[3] 2_x_2_Array.$FSAMP DB(| PPC_ETheta(0,1,0,2,1)| )[3] 2_x_2_Array.$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 1.81111 x -0.0224852 S(1,1) 2_x_2_Array Microstrip Antenna Design 19 www.cadence.com/go/awr

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