A NOVEL DESIGN OF MODIFIED COMPOSITE RIGHT/LEFT-HANDED UNIT CELL

Design procedure for a modifled Composite Right/Left Handed (CRLH) unit cell is represented. The ferroelectric interdigital capacitor (IDC) is used as a tuned capacitor, and spiral inductor is utilized to implement inductors. A modifled CRLH unit cell is attained by moving the shunt inductor of conventional unit cell to both ends with doubled values. In this manner, only one bias network would be required for each unit cell. The parameters of the designed unit cell are obtained so that the Bloch impedance to be equal to 50› and the Bloch propagation constant to have one zero at the operational frequency. The operational frequency is chosen equal to 11:45GHz, which is in the Ku-band and in middle of the up-link satellite communications. To design the modifled unit cell, initially, the unit cell without a shunt capacitor is constructed. This would result in ƒ-model structure for which the element dimensions are varied to reach the desired values. Next, the shunt capacitor is added to the model and its length is varied until the balanced condition is achieved.