This paper proposes a two-parameter block triangular splitting(TPTS)preconditioner for the general block two-by-two linear systems.The eigenvalues of the corresponding preconditioned matrix are proved to cluster aroun...This paper proposes a two-parameter block triangular splitting(TPTS)preconditioner for the general block two-by-two linear systems.The eigenvalues of the corresponding preconditioned matrix are proved to cluster around 0 or 1 under mild conditions.The limited numerical results show that the TPTS preconditioner is more efficient than the classic block-diagonal and block-triangular preconditioners when applied to the flexible generalized minimal residual(FGMRES)method.展开更多
Today's antennas have to operate in multiple resonant frequencies to satisfy the need of recent advances in communication technologies.This paper presents split ring resonator based triangular multiband antenna wh...Today's antennas have to operate in multiple resonant frequencies to satisfy the need of recent advances in communication technologies.This paper presents split ring resonator based triangular multiband antenna whose antenna performance is enhanced with the help of frequency selective surfaces(FSSs).The antenna has multiple resonances at S,C,and X bands.An array of 4×3 crisscross-shaped unit cells are arranged to form the FSS layer.The antenna is fed with a microstrip line feeding technique.The proposed antenna operates at 3.5 GHz,4.1 GHz,5.5GHz,9.4GHz,and 9.8 GHz with a better return loss and gain.Simulated and measured results yield a good match.展开更多
基金the National Natural Science Foundation of China under Grant Nos.61273311 and 61803247.
文摘This paper proposes a two-parameter block triangular splitting(TPTS)preconditioner for the general block two-by-two linear systems.The eigenvalues of the corresponding preconditioned matrix are proved to cluster around 0 or 1 under mild conditions.The limited numerical results show that the TPTS preconditioner is more efficient than the classic block-diagonal and block-triangular preconditioners when applied to the flexible generalized minimal residual(FGMRES)method.
文摘Today's antennas have to operate in multiple resonant frequencies to satisfy the need of recent advances in communication technologies.This paper presents split ring resonator based triangular multiband antenna whose antenna performance is enhanced with the help of frequency selective surfaces(FSSs).The antenna has multiple resonances at S,C,and X bands.An array of 4×3 crisscross-shaped unit cells are arranged to form the FSS layer.The antenna is fed with a microstrip line feeding technique.The proposed antenna operates at 3.5 GHz,4.1 GHz,5.5GHz,9.4GHz,and 9.8 GHz with a better return loss and gain.Simulated and measured results yield a good match.
