Том 61, № 3 (2018)

A printed small size (12×16.5 mm) ACS-fed e-shaped uniplanar antenna is proposed for dual band applications. The multiband operating characteristics have been achieved by integrating e-shaped radiating strips to the 50ΩACSfeed line. Two simultaneously operating wide bands have been generated by using optimized radiating branch strips for the multiband applications. For obtaining size reduction and wider impedance bandwidth, e-shaped meandered elements are chosen in the design. The proposed design features the bandwidth (VSWR < 2, reflection coefficient below–10 dB) of 100 MHz in 2.4–2.5 GHz, and 2100MHzin 4.0–6.1 GHz. The developed multiband antenna can be useful for several wireless communication applications, such as 2.4 GHz Bluetooth/RFID,WLAN(2.4/5.2/5.8 GHz), WiMAX (5.5 GHz), US public safety band (4.9 GHz), ISM band, radio frequency energy harvesting and internet of things (IoT) applications.

The nonlinear interaction of high power millimeter (mm) electromagnetic waves with silicon integral p-i-n structures placed in a metal waveguide is theoretically investigated. The level of double injection of charge carriers due to detection of high intensity millimeter wave electric field in p-i-n structures is estimated. A mathematical model of the mutual influence of electromagnetic waves and injected charge carriers in the active region of p-i-n structures is formulated. A numerical solution of the nonlinear Helmholtz equation supplemented by proper boundary conditions on the active region boundary is obtained. The effect of high-power electromagnetic waves leads to an excessive injection of carriers into the active region of the semiconductor between p⁺-i, n⁺-i injection junctions and redistribution of the electric field in the structure. The reflection and transmission coefficients vary rapidly with the change in the input amplitude of the electromagnetic wave. This leads to bistability of these coefficients. The bistability is more pronounced in the low-frequency part of the mm range.

The work considers a queuing system of the G/M/1 type that simulates service of self-similar traffic in a NodeB (e-NodeB) base station of a mobile operator. The feature of quality of service (QoS) characteristics estimation process for the self-similar traffic defined by the Weibull distribution is the solution based on the Laplace–Stieltjes transformation. The Laplace transformation for an infinite number of items under the Weibull distribution condition was found. It was shown that this series was equiconvergent to some convergence domain. The following QoS characteristics were obtained for the self-similar traffic: the average amount of time that a request spends in the system; the average number of requests waiting in the queue and the average queue length. The obtained results allowed to consider the real values of traffic serviced by a NodeB (e-NodeB) for their optimal deployment over a covered territory at the stage of frequency planning and operation of the 3G/UMTS and 4G/LTE networks.