Printed ultra-wideband stepped-circular slot antenna with different tuning stubs

An UWB slot antenna without stub tuning

“…In contrast to reported monopole-like slot antennas with stub tuning, fed either by a CPW [3,6,7,[15][16][17][18] or by a microstrip line [2,[5][6][7][8][9][10][11][12][13][14]27], it is essential to excite and then tune the antenna. The configuration in this article proposed feeding the radiator directly by a slot line without any other requirements, like a stub and its possible complications, as choosing the proper size, geometry, and location.…”

“…The proposed antenna is based on the generalization and extension of Babinet's principle: the bandwidth of a slot antenna is wider as the slot becomes broader [1]. Printed slot antennas can be fed by a microstrip line [2,3,[5][6][7][8][9][10][11][12][13][14], coplanar waveguide (CPW) [3,4,6,7,[15][16][17][18], or by a coaxial line [1,6,[19][20][21][22][23].…”

“…Slot antennas can be built as a single-layer metallic structure and fed by a CPW [1,3,4,6,7,[15][16][17][18][19][20][21][22][23][24][25][26], or as a two-layer and fed by a microstrip line [2,3,[5][6][7][8][9][11][12][13]27], or even a multilayer structure [14]. They can exhibit wideband [2][3][4][5][6][7][8]11,13,[17][18][19][21][22][23][25][26][27] or multiband behavior [12,[14][15][16]…”

“…This transition is usually implemented by a stub feed [2][3][4][5][6][7][8][9]11,12,[14][15][16][17]19,[24][25][26][27]. Even when the antenna bandwidth depends on the slot geometry [2][3][4][5][6][7][8][12][13][14][15][16][17][18][19]21,23,[25][26][27], it also depends on the stub size and form [2][3][4][5]7,8,[12][13][14][15][16][17][18]. In addition, the feed gap ...…”

“…In 1989, Rentzepis first proposed the technique that high-density three-dimensional optical information storage was achieved with some inorganic or organic molecules material possessing two-photon nonlinear absorption properties [1]. Therefore, based on femtosecond laser threedimensional optical storage is a more promising approach, it has become a research hotspot in this field [2][3][4][5][6][7][8]. In threedimensional optical storage, the microburst storage is an important method [9,10].…”