Przemyslaw Piasecki

Accuracy enhancement of material characterization in sub-THz range

In this paper many aspects of material characterization in sub-THz frequency range are shown. Methods of reducing unwanted reflections from construction of the measurement setup and from the sample under test are proposed. The influence of lens tilt on electromagnetic field distribution in location of the sample is investigated.

120 GHz – 135 GHz CPWG to dielectric waveguide transition and its capability with using different LTCC materials

In this paper an LTCC transition between CPWG and dielectric waveguide for 120 GHz - 135 GHz is presented. Comparison between simulated results of a transition for two kinds of used LTCC materials: Ferro A6-M and DuPont are shown. Designed LTCC transition reflection coefficient is between -15 dB and -20 dB respectively for Ferro A6-M and DuPont GreenTape 951 LTCC materials. The S21 transmission coefficient is better than - 5 dB for Ferro A6-M and better than -10 dB for DuPont.

A novel structure of broadband wire antenna with orthogonal polarization in UHF and VHF bands

This letter presents a novel conception of compact, broadband wire antenna with orthogonal polarization in VHF and near UHF band hereinafter called VHF_II. The design is based upon a Bowtie-shape and modified Batwing-shape of antenna apertures fed with coaxial line with properly matched band - pass filters. A suitable combination of both Bowtie and Batwing antenna shapes makes it possible to obtain vertical polarization in VHF_I (88 MHz ÷ 108 MHz) and horizontal polarization in VHF_II (174 MHz ÷ 230 MHz) without using antenna crossed shape. The radiation of designed structure was numerically modelled using CST Studio electromagnetic solver. Impedance matching is greater than -10 dB in both VHF_I and VHF_II antenna working bands. Gain, using wire shield, equals about 7 dBi for vertical and about 8 dBi for horizontal polarization.

Measurement of an omnidirectional antenna pattern in an anechoic chamber and an office room with and without time domain signal processing

In this paper the ability to measure a radiation pattern of omnidirectional antennas without using an anechoic chamber is presented. For this purpose, the time domain technique is used and the influence of this solution on an antenna radiation pattern is shown. Moreover difference between radiation patterns obtained from an anechoic chamber and office room using postprocessing in time domain are presented.

High resolution patterns on LTCC substrates for microwave applications obtained by screen printing and laser ablation

The main objective of the paper is presentation of challenges in technological aspect of manufacturing conductive paths on LTCC (low temperature co-fired ceramics) substrates. The effects of research are presented basing on the example of high resolution 3D antennas for sub-THz scanner performed using LTCC technology. The impact of screen preparation and printing conditions (the angle and pressure of squeegee, the mesh size) as well as deformations and shrinkage of the structure during co-firing, on the obtainment of desired pattern dimensions, is discussed.

The investigation of VHF array antenna radiation pattern simulated in free space and in a semi-anechoic chamber

This paper presents the challenges involved in adapting the large size Electromagnetic Compatibility (EMC) semi-anechoic chamber for VHF array antenna measurements. The comparison between simulated antenna characteristics in free space and in presented semi-anechoic chamber is shown and discussed. Also the simulations in CST Microwave Studio simulator of commercially available AEP-36 pyramidal absorbing cones are introduced.

Investigation of LTCC leaky wave antenna operated in mm-wave band

This paper presents the challenge involved in designing LTCC leaky wave antenna operated in mm-wave band. Taking account a possibility of using LTCC technology in the mm wave, some advantages and limitations of its technology in these frequency band are described. Moreover the transition between waveguide to designed antenna is presented and the simulation results of each parts of the structure are shown. Moreover some manufactured parts of the antenna with using LTCC technology is shown. The antenna is optimized to obtain a minimum radiation pattern squint in all operated frequency bandwidth.