A Novel Frequency Reconfigurable Yagi-Like MIMO Antenna System

A compact single layer frequency reconfigurable Yagi-like multiple-input-multiple-output (MIMO) antenna system is presented based on slot excitation. The traditional omnidirectional pattern of a slot antenna is made directional by using a single slot based complementary wideband reflector (CWBR) element. The total size of the CWBR is 9.5$\times$ 70mm
²
. The proposed MIMO antenna system can cover the frequency bands from 2.5–4.5 GHz, with a minimum bandwidth of 200 MHz. The frequency reconfigurability is achieved using varactor diodes. The overall size of the proposed antenna system is 40$\times$ 100$\times$ 0.76mm
³
, making it suitable for compact wireless handheld devices. The antenna system satisfies Yagi as well as MIMO performance metrics.