Wideband Magnetoelectric Dipole Phased Array With SICL Feed and Reactive Impedance Surface

A compact wideband magnetoelectric (ME) dipole antenna array with substrate-integrated coaxial line (SICL) feed is proposed for wide beam steering (BS) applications. The SICL line is transformed into a grounded coplanar waveguide (GCPW) to feed the ME dipole element. The element is first miniaturized using a closed U-shaped slot realized on SICL-GCPW ground, C-shaped shorting strip on ME dipole, and reactive impedance surface (RIS) loading. The element achieves an impedance bandwidth (IBW) of 59.44% at the center frequency (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rm f_{0}$ </tex-math></inline-formula>) of 22.125 GHz while maintaining a compact size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rm 0.33 \lambda _{0}\, \times \, \rm 0.28 \lambda _{0}$ </tex-math></inline-formula> (excluding RIS), where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rm \lambda _{0}$ </tex-math></inline-formula> is free space wavelength at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rm f_{0}$ </tex-math></inline-formula>. A corporate feed network with low port imbalances is designed using SICL technology, which is used to realize an eight-element uniform linear array (ULA). Experiments reveal a measured IBW of 55.43% and a measured peak realized gain of 13.2 dBi (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$11.53~\rm \pm ~1.67$ </tex-math></inline-formula> dBi). BS measurements at 24 and 27 GHz show realized gain BS to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rm \pm 45^{\circ } $ </tex-math></inline-formula> with worst case total scan loss (TSL)/sidelobe level (SLL)/cross-polarization discrimination of 3/-10.9/15.2 dB and 4.13/-5.2/14.8 dB, respectively. Array prototypes use Rogers 4003 with width <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.96\lambda _{0}$ </tex-math></inline-formula> (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rm f_{0} =22.15$ </tex-math></inline-formula> GHz).