Four-port Configuration Research Articles

UWB-MIMO 4-Port Fractal Antenna with Reduced Mutual Coupling

Abstract: UWB MIMO antenna loaded structure Mutual coupling between the four radiating elements is obtained to be less than - 25 db. The patterns of radiation are stable over the operating range and a peak gain of 4.5 dB is obtained at 7.5GHz and Return loss is obtained less than 10dB. Simulation is conducted using HFSS simulation tool and printed on a 30 X 30 X 1.6 mm3 FR4 material. 4 linear SRR structures are used between adjacent elements to ensure good isolation. MIMO antenna with grounded stubs and fractal geometry are used to improve isolation and to achieve wide band phenomena. UWB-MIMO antenna using to achieve better isolation. The UWB MIMO 4-port fractal antenna combines the characteristics of ultra-wideband operation, multiple input multiple output capability, four-port configuration for simultaneous data streams, and a fractal antenna design for wide bandwidth and compact size. This makes it suitable for high-speed, reliable communication in applications requiring UWB technology, such as high-speed data transfer, localization, and radar systems. By integrating a copper rectangular plane between ports, interference and crosstalk are minimized, enhancing the antenna's capability to handle multiple input and output signals efficiently. This innovative design approach not only improves isolation but also contributes to the antenna's overall effectiveness in various communication applications.

A Novel Four-Port Configuration With Improved Efficiency and Power-Handling Capability for Diode-Based Doublers in Submillimeter Waves

We present a novel four-port balanced configuration for Schottky diode-based doublers featuring improved power-handling capability and conversion efficiency. The circuit design includes two frequency doubler cells associated with compact functional networks, which provides unique phase differences for those generated harmonic currents. So, this circuit could achieve the inherent suppressions on odd-order harmonics as well as the fourth harmonic without any filter, which guarantees the efficient frequency multiplying and overcomes the efficiency degradations exists in conventional power-combined multipliers. Example of the diode-based frequency doubler, operating up to 115 GHz, has been demonstrated based on this prototype. At room temperature, the fabricated doubler exhibits a 13.6% 3-dB bandwidth and a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim$</tex-math> </inline-formula> 46.1% peak conversion efficiency (at 105 GHz) for a nominal input power of 240–360 mW. At the same time, this module could deliver maximum power over 230 mW with the maximum achievable input power level.

Theoretical and Experimental Studies of a Switched Inertance Hydraulic System in a Four-Port High-Speed Switching Valve Configuration

The switched inertance hydraulic system (SIHS) is a novel high-bandwidth and energy-efficient digital device which can adjust or control flow and pressure by a means that does not rely on throttling the flow and dissipation of power. An SIHS can provide an efficient step-up or step-down of pressure or flow rate by using a digital control signal. In this article, analytical models of an SIHS in a four-port high-speed switching valve configuration are proposed, and the system dynamics and performance are investigated theoretically and experimentally. The flow responses, system characteristics, and power consumption can be predicted effectively and accurately by using the proposed models, which were validated by comparing with experiments and with numerical simulation. The four-port configuration is compared with the three-port configuration, and it is concluded that the former one is less efficient for valves of the same size, but provides a bi-direction control capability. As bi-direction control is a common requirement, this constitutes an important contribution to the development of efficient digital hydraulics.

Ring fiber resonators based on fused-fiber grating add–drop filters: application to resonator coupling

We introduce a fiber ring optical resonator based on adiabatic fused-fiber grating couplers. The coupling of a through fiber to the resonator is controlled by the strength of the fiber Bragg gratings. By using two of these couplers and incorporating erbium-doped (ED) fiber in the ring, we control the internal loss of the ring by pumping the ED fiber. The transmission spectra of the through port and the drop port of a four-port configuration, a ring coupled to two waveguides, are measured. We show that the loss/coupling ratio of the ring-fiber system can be changed and thus that the transmission properties of the fiber can be controlled.