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Experimental comparison of absorber and conductive floor automotive near field antenna measurement systems
Large truncated spherical near-field systems with conductive or absorbing floors are typically used in the measurement of the performances of vehicle-installed antennas. The main advantage of conductive floor systems is the ease of accommodation of the vehicle under test, but their performances are affected by the interaction with the reflecting ground floor. Instead, absorbing-based systems emula
Determining the nominal body contour image using wideband millimeter-wave radar for characterizing person-worn threats
Precise characterization of concealed person-worn objects will speed up the passenger screening process by reducing the rate of nuisance alarms, while also enhancing the airport security imaging systems. This paper presents an automatic, real-time method for wideband millimeter-wave radar identification of the nominal surface contours of the human body ? even with affixed foreign objects or when a
Directive mmWave radio channel modeling in a ship hull
Wireless connectivity has been realized for multiple environments and different frequency bands. However, little research exists about mmWave communication in industrial environments. This paper presents the 60 GHz double-directional radio channel for mmWave communication in a ship hull for Line-of-Sight (LOS) and non-Line-of-Sight (NLOS) conditions. We performed channel measurements using the Ter
Numerical simulation of characteristics of propagation of symmetric waves in microwave circular shielded waveguide with a radially inhomogeneous dielectric filling
The paper presents a numerical simulation of the propagation characteristics of symmetric -type and -type waves in microwave circular shielded waveguide with radially inhomogeneous dielectric filling. Using the modified Galerkin method, the calculation of a circular two-layer shielded waveguide was carried out, as a result of which the distribution of the electromagnetic field of the waveguide wit
In-band RCS reduction antennas using an EBG surface
The paper has proposed a multilayer, polarization rotation featured, low radar cross-section (RCS) antenna using electromagnetic band-gap (EBG)-based frequency selective surface (FSS) at 8.25 GHz. Cross-shaped EBG unit cells offer zero reflection phase and ?25 dB reflection magnitude at 8.25 GHz. The FSS layer consists of eight cross-shaped EBG unit cells sandwiched between two substrates to offer
Superstrate-based patch antenna array with reduced in-band radar cross section
To design a low radar cross section (RCS) antenna, the major concern is not only to reduce scattering, but also to maintain its radiation parameters, viz. gain, voltage standing wave ratio (VSWR), etc. This paper presents a simple configuration of low RCS microstrip patch array with a periodic structure-based superstrate. The ground of the array is designed as reduced ground plane with high impeda
Investigations on a circular UWB antenna with Archimedean spiral slot for WLAN/Wi-MAX and satellite X-band filtering feature
In this article a compact circular monopole antenna is represented with dimensions of 38.87 × 24.00 × 1.60 mm applicable for WLAN/Wi-MAX and satellite band rejection characteristics. The impedance bandwidth is 9.42 GHz (3.12?12.54 GHz) for the final antenna with an equivalent fractional bandwidth of about 120.31%, producing triple notched bands centered at 3.95, 5.20 and 8.90 GHz with assistance o
Time-modulated linear array synthesis with optimal time schemes for the simultaneous suppression of sidelobe and sidebands
An efficient analysis of time-modulated array (TMA) toward realizing less-attenuating radiation patterns with simultaneously suppressed sidelobe and sidebands is presented in this paper. In this framework, an optimal outer element-controlled time sequence is derived. The proposed time scheme, along with optimized array excitations, is profitably applied for the desired solution. TMAs are considere
Fast sparse image reconstruction method in through-the-wall radars using limited memory Broyden?Fletcher?Goldfarb?Shanno algorithm
Compressed sensing allows recovery of image signals using a portion of data ? a technique that has drastically revolutionized the field of through-the-wall radar imaging (TWRI). This technique can be accomplished through nonlinear methods, including convex programming and greedy iterative algorithms. However, such (nonlinear) methods increase the computational cost at the sensing and reconstructio
Telemetry antennas withstanding very high accelerations and centrifugal forces
We present the design steps of a coaxial dipole antenna for telemetry applications under extreme conditions of accelerations and centrifugal forces. Both, electromagnetic and mechanical designs are explained, as well as performance compromises that have to be made between both domains. The experimental results are given in the following part of the article, before some details on the instrumented