The E-plane waveguide branch directional couplers are analyzed by a method which combines the multimode network theory with rigorous mode-matching approach. The electromagnetic field components are expanded by the sup...The E-plane waveguide branch directional couplers are analyzed by a method which combines the multimode network theory with rigorous mode-matching approach. The electromagnetic field components are expanded by the superposition of LSEx modes rather than TE and TM modes in the mode-matching procedure. Meanwhile, the electromagnetic problem is transferred into the network problem through the mode-matching treatment. It is shown that the present method has the advantages of simplicity and less computation without affecting the accuracy of the calculation.展开更多
A method of designing an E-plane power combiner composed of two quarter-arc bent rectangular waveguides is proposed for sub-THz and THz waves. The quarter-arc bent-waveguide power combiner has a simple geometry which ...A method of designing an E-plane power combiner composed of two quarter-arc bent rectangular waveguides is proposed for sub-THz and THz waves. The quarter-arc bent-waveguide power combiner has a simple geometry which is easy to design and fabricate. By HFSS codes, the physical mechanism and performance of the power combiner are analyzed, and the relationship between the output characteristics and the structure/operating parameters is given. Simulation results show that our power combiner is suitable for the combining of two equalpower and reversed-phase signals, the bandwidth of the combiner is wide and can be adjusted by the radius of the quarter-arc, and the isolation performance of the combiner can be improved by adding thin film resistive septa at the junction of two quarter-arc bent waveguides. Meanwhile, an approximate method based on the analytic geometrical analysis is given to design this power combiner for different frequency bands.展开更多
We propose and analyze a submicron stub-assisted ultrafast all-optical plasmonic switch based on nonlinear MIM waveguide. It is constructed by two silicon stub filters sandwiched by silver cladding. The signal wavelen...We propose and analyze a submicron stub-assisted ultrafast all-optical plasmonic switch based on nonlinear MIM waveguide. It is constructed by two silicon stub filters sandwiched by silver cladding. The signal wavelength is assumed to be 1550 nm. The simulation results show a ?14.66 dB extinction ratio. Downscaling the silicon waveguide in MIM structure leads to enhancement of the effective Kerr nonlinearity due to tight mode confinement. Also, using O+ ions implanted into silicon, the switching time less than 10 ps and a delay time less than 8 fs are achieved. The overall length of the switch is 550 nm.展开更多
In this study, we constructed a 4-element linear array antenna using four 20 GHz band microstrip patch antennas with a structure such that the signal is fed to the patch antennas from open-end coplanar waveguides with...In this study, we constructed a 4-element linear array antenna using four 20 GHz band microstrip patch antennas with a structure such that the signal is fed to the patch antennas from open-end coplanar waveguides without contact. We investigated factors related to the design of linear array patch antennas. To adjust the maximum radiation direction and reduce return loss, we optimized the spacing between the elements and their shape. With an element spacing of 11.50 mm, patch width of 3.90 mm, and patch length of 4.15 mm, we obtained a resonance frequency of 20.05 GHz and a return loss of -29.59 dB at the resonance frequency. However, in the case of a 4-element linear array antenna structure, undesired resonances occurred in frequency bands other than the design resonance frequency band of 20 GHz. To suppress these undesired resonances and obtaining stable operation at the design frequency, we propose a new structure in which the feed line is loaded with a short stub, and show through computer simulations that the occurrence of undesired resonances can be sufficiently suppressed. Furthermore, we demonstrate the problem of radiation gain reduction caused by introducing a short stub, propose a design method for a new structure in which the feed line has slits between the stubs, and show improvement of the antenna gain by 0.5 dBi.展开更多
文摘The E-plane waveguide branch directional couplers are analyzed by a method which combines the multimode network theory with rigorous mode-matching approach. The electromagnetic field components are expanded by the superposition of LSEx modes rather than TE and TM modes in the mode-matching procedure. Meanwhile, the electromagnetic problem is transferred into the network problem through the mode-matching treatment. It is shown that the present method has the advantages of simplicity and less computation without affecting the accuracy of the calculation.
基金Supported by the National Natural Science Foundation of China under Grant No 11075032the Fundamental Research Funds for the Central Universities under Grant No ZYGX2014J033
文摘A method of designing an E-plane power combiner composed of two quarter-arc bent rectangular waveguides is proposed for sub-THz and THz waves. The quarter-arc bent-waveguide power combiner has a simple geometry which is easy to design and fabricate. By HFSS codes, the physical mechanism and performance of the power combiner are analyzed, and the relationship between the output characteristics and the structure/operating parameters is given. Simulation results show that our power combiner is suitable for the combining of two equalpower and reversed-phase signals, the bandwidth of the combiner is wide and can be adjusted by the radius of the quarter-arc, and the isolation performance of the combiner can be improved by adding thin film resistive septa at the junction of two quarter-arc bent waveguides. Meanwhile, an approximate method based on the analytic geometrical analysis is given to design this power combiner for different frequency bands.
文摘We propose and analyze a submicron stub-assisted ultrafast all-optical plasmonic switch based on nonlinear MIM waveguide. It is constructed by two silicon stub filters sandwiched by silver cladding. The signal wavelength is assumed to be 1550 nm. The simulation results show a ?14.66 dB extinction ratio. Downscaling the silicon waveguide in MIM structure leads to enhancement of the effective Kerr nonlinearity due to tight mode confinement. Also, using O+ ions implanted into silicon, the switching time less than 10 ps and a delay time less than 8 fs are achieved. The overall length of the switch is 550 nm.
文摘In this study, we constructed a 4-element linear array antenna using four 20 GHz band microstrip patch antennas with a structure such that the signal is fed to the patch antennas from open-end coplanar waveguides without contact. We investigated factors related to the design of linear array patch antennas. To adjust the maximum radiation direction and reduce return loss, we optimized the spacing between the elements and their shape. With an element spacing of 11.50 mm, patch width of 3.90 mm, and patch length of 4.15 mm, we obtained a resonance frequency of 20.05 GHz and a return loss of -29.59 dB at the resonance frequency. However, in the case of a 4-element linear array antenna structure, undesired resonances occurred in frequency bands other than the design resonance frequency band of 20 GHz. To suppress these undesired resonances and obtaining stable operation at the design frequency, we propose a new structure in which the feed line is loaded with a short stub, and show through computer simulations that the occurrence of undesired resonances can be sufficiently suppressed. Furthermore, we demonstrate the problem of radiation gain reduction caused by introducing a short stub, propose a design method for a new structure in which the feed line has slits between the stubs, and show improvement of the antenna gain by 0.5 dBi.
基金Supported by National Natural Science Foundation of China,11447118,11247032,11365011Youth Science Foundation of Science and Technology Department of Jiangxi Province,20151BAB212004,20151BAB212012~~
