Reflection phase characteristics of active EBG structures using varactor diodes on a single layer

A proposed active Electromagnetic Band-gap (EBG) can control the reflection phase using a varactor diode instead of by changing structure physically. This structure uses only one diode per four unit cells. It can operate as a group cell changing the reflection phase by simply varying varactor capacitances through an appropriate biasing voltage. The conventional loading of a single varactor for each of the unit cells of the EBG is overcome by connecting the unit cells to a feeding network directly without via. Moreover, this structure does not need via and uses single layer so it is simple to fabricate and can decrease cost. The proposed EBG structure can cover the reflection phase range of the group cell from -132° to 122° at 10 GHz.