Technology And Application Of Low Imped Ance Slot Line

The conventional slot line is formed by a thin slit on the ground conductor side of the dielectric substrate,and on the other side is free of a metal conductor,is a planar structure transmission line.With the development of the microwave integrated circuits,the slot line may become more and more popular.However,the characteristic impedance of a conventional slot line is generally high,restricting many uses of the slot line.Considering this disadvantage of the conventional slot line,this paper presents a low characteristic impedance slot line using metalized via and patch loading techniques.The characteristic impedance of this transmission line is much lower than that of the conventional slot line,and can be varied on a wide range.The main work of this paper includes:1)A metallized via and loaded patch slot line are proposed,in which two rows of periodic metallized via are etched on both sides of a slot gap.Two arrays of metallized via are equivalent to two metal walls and two metal patches are symmetrically loaded on the other side of the dielectric substrate to further reduce the characteristic impedance of the slot line.The definition of the characteristic impedance and propagation constant of this new low impedance slot line are analyzed.The characteristic impedance and propagation constant of the new low impedance slot line are calculated by using the electromagnetic simulation software HFSS.The transmission characteristics of this slot line are studied.2)A slot antenna structure with metallized via and loaded patch is proposed.The antenna is miniaturized by using the step impedance resonator(SIR)principle.Two miniaturized stepped impedance slot antennas with different thicknesses are designed and the performances of the two slot antennas are compared.3)A dual-band step impedance slot antenna is designed.This antenna has both magnetic current gap and current patch radiation.The first frequency band of the slot antenna is the radiation of the slot,the second frequency band is the radiation of the patch,and it has the characteristic of miniaturization and strong application value.