K. V. Lemberg

Magnetically Tunable Resonant Phase Shifters for UHF Band

This paper presents a new type of magnetically tunable phase shifter. The shifter has the structure of microstrip bandpass filter on a substrate containing magnetic material whose magnetic permeability is controlled by magnetic field due to ferromagnetic resonance. The phase shifters operation is based on the fact that phase shift in a bandpass filter changes with tuning of its central frequency. Two types of devices were designed and fabricated for the UHF band. One of them has a five-layer NiFe film as an active medium and demonstrates a figure of merit of 40°/dB achieved already at 20 Oe of the controlling magnetic field in 10% of the relative operational bandwidth. The second device with YIG ferrite as an active medium gave 360° tunable phase shift in 5% operational bandwidth that corresponds to the figure of merit of 150°/dB (3.1°/dB·Oe).

X-band substrate integrated waveguide (SIW) slot antenna array

2×4 element waveguide-slot antenna array at 8 GHz is described. Antenna is built using substrate integrated waveguide (SIW) technology. Simulated and measured radiation patterns and reflection coefficient are presented.

High gain substrate integrated waveguide slot antenna array

Linear and planar substrate integrated waveguide slot antenna arrays at 14.5 GHz are described. Simulated and measured characteristic of fabricated 32 × 16 slot antenna array are presented, antenna gain 25 dBi is achieved.

Implementation of antenna near-field scanning without using probe position sensors

In this paper the design of a near-field scanner for antenna measurements is presented. A distinctive feature of the scanner is the absence of probe position sensors. The control circuit is proposed which allows generating the trigger signal for the vector network analyzer during continuous scanning without using information from the probe position sensors. Experimental results demonstrates that the proposed approach allows to perform fast and high quality antenna near-field measurements.

GNSS antenna characteristics using bi-orthogonal far-field measurement

This paper describes a technique for characterization of GNSS antennas, using bi-orthogonal (two orthogonal linear polarizations) far-field measurements. The main feature of the proposed technique is that measurement can be done using only one measuring antenna with linear polarization. The formulas for calculation according to the bi-orthogonal measurements of the radiation patterns for co- (right-handed) and cross- (left-handed) circular polarizations, axial ratio, multipath ratio, coordinates and instability of the phase center position are given. An example of characteristics of a spiral slot GNSS antenna using the proposed technique is discussed.

Phased array antenna with combined electronical and mechanical beam steering for satellite networks

Phased array antenna with combined electronical and mechanical beam steering in elevation plane is considered. The analytical calculating results are presented. The simulation results of designed investigated antenna system are introduced.

Tunable resonant microstrip phase shifter with the magneto dielectric substrate

The new design of a tunable microstrip phase shifter is proposed. It is based on the resonant microstrip structure in which a magnetodielectric is used as a substrate with controlled electromagnetic characteristics. The design of the phase shifter is characterized by a high degree of diminutiveness and high figure of merit. The manufactured breadboard of a five-resonator phase shifter demonstrated a controllable phase shift of 360° with a figure of merit of 150 °/dB.

A wide-angle mechanoelectrical steering antenna system based on multilayer dielectric wedge structure

The work presents the study of multilayer structure based on flat dielectric wedges which provides linear phase shift for wide-angle beam steering antennas. The results of numerical simulation are given including the radiation patterns of deflecting structure and of the whole antenna system based on it. Also some methods for improving the performance of the examined system were studied. The presented antenna system showed the ability of mechanoelectrical beam steering within the range of ±45° in elevation plane and 360° in azimuthal plane. The directivity deterioration in elevation plane reached 3 dB relative to zero direction.

Thin Magnetic Films with Artificial Texture on Substrate: Microwave Properties

Using the scanning spectrometer of ferromagnetic resonance (FMR) the experimental dependences of the resonance field and FMR line width of thin permalloy magnetic films, which were deposited in vacuum on the substrate with an artificial texture, were obtained. The texture was produced by putting parallel grooves using a diamond cutter on glass substrates with period from 5 to 100 μm. It was found that the presence of the texture led to a considerable increase of the resonance field and FMR line width, when the external field was directed orthogonal to the grooves. On the base of a numerical micromagnetic simulation the explanation of the nature of observable in thin magnetic films effects was given.

Formulation of the Hansen-Chu-McLean relations for the non-harmonic signals

In the paper estimation of the fundamental performance limit for short antennas operating in the ultra-short pulses and ultra-wideband signals radiation mode is performed. Generalized quality factor of the small antenna with respect to its dimensions and signal spectral density is obtained, which may be considered as an extension of the McLean theory to the case of non-harmonic signals. Some examples of the obtained relations implementation are given.