Volume 62, Nº 4 (2019)

The detection of moving target (MTI) against clutter background represents one of the most important goals of a radar system. To achieve this objective,itisnecessarytosuppress or cancel the clutter returns with as small suppression of the target signal as possible. In this regard, MTI radar is capable of detecting such type of targets in the presence of interferers. Radar MTI is of great interest in civil and military applications, where it reduces the returns from stationary or slowly moving clutter. Additionally, in order to make decisions on the target presence, the MTI processing may be applied with automatic detection. In this situation, the CFAR detection is a common style of adaptive algorithms employed in radar systems to detect target returns against a background of noise, clutter and interference. However, the presence of MTI complicates the analysis of the detection system performance since its output sequence is correlated even though its input sequence may be uncorrelated. Our goal in this paper is to analyze the performance of a radar signal processor that consists of a nonrecursive MTI followed by a square-law integrator and a new version of CFAR circuit detection; the operation of which is based on the hybrid combination of CA and TM algorithms. The processor performance is evaluated for the case where the background environment is assumed to be ideal (homogeneous) as well as in the presence of spurious target returns amongst the contents of the reference cells. The numerical results exhibit that the processor performance can be enhanced through either increasing the number of incoherently integrated pulses or decreasing the correlation among consecutive sweeps, given that the rate of false alarm is keeping constant.

—Processes occurring in the setup for contactless measurement of conductivity of liuids have been considered. The experimental study of the relationship of the oscillating circuit Q-factor as a function of the specific resistance of liuid was performed using the electrode and electrodeless methods of measurements. Freuency relationships of additional attenuation d in the oscillating circuit caused by the presence of liuid with specific resistance ρ in inductively coupled capillary solenoid were investigated in the freuency range 2.2–8.8 MHz. It was shown that the impact of skin effect was significant for the considered values of ρ and the additional attenuation was described by formula d = −a₀(f) + a₁(f)ρ^1/2, where function a₁(f) is proportional to f^3/2, while function a₀(f) is proportional to f². Owing to different freuency dependences of functions a₁(f) and a₀(f), the frequency relationship of the relative depth of skin layer in liquid electrolyte was obtained in explicit form: h / r_cp = A(f)ρ^½af^½ρ^½, where a is the constant that does not depend on frequency and specific resistance of liquid.

In this paper the effect of copper and graphene conductive ink material on antenna performance is compared. The patch structures are simulated using HFSS software. The designed antenna is resonating around 1.2 GHz giving reflection coefficient below −10 dB. The simulated and fabricated modified bow-tie antenna design have impedance bandwidth of 15 (simulated), 12 (copper), and 13.5 MHz (graphene), respectively, which are suitable for LTE (QUALCOMM), WiMAX, Wi-Fi applications. This modified design consists of various types of slots introduced at various places of bow-tie arm in order to get desired bandwidth and for the improvement in antenna performance parameters. This proposed antenna will work in UHF (Ultra High Frequency) band at 1.2 GHz. Compare to conventional bow-tie antenna this modified design will give better antenna performance parameters. In this work we have compared various performance parameters like return loss, VSWR and bandwidth for each design. These parameters have been validated for proposed model for resonating frequency.