The dominant E-field generation in the optimized straight CTL cell by using a wideband balun

This paper designes an optimized straight CTL cell whose uniform area is 20 mm × 20 mm and generates the dominant E-field and H-field to calibrate small EM field probes by using a wideband balun and a wideband power divider. The fabricated optimized straight CTL cell can operate on the broadband frequency range up to 2800 MHz except 2170 MHz. The fabricated two baluns, low frequency band balun and high frequency band balun, that consisted of a divider and two 3-dB quadrature coupler within 0.27 dB of the amplitude difference and 180 ± 2.6° of the phase difference from 800 to 3000 MHz. And, the fabricated two power divider use the 3-section Wilkinson power divider type. The field uniformity of the uniform area in the fabricated optimized straight CTL cell is within +1 dB. The measured dominant E & H-field and resonant frequencies of the designed CTL cell agree well with the simulated results.