Substrate-Integrated Waveguide Microwave Sensor for Water-in-Diesel Fuel Applications

Wideband Circularly Polarized Millimeter Wave Hemispherical Dielectric Resonator Antenna

A novel approach is proposed to design a circularly polarized (CP) hemispherical dielectric resonator antenna (DRA) with a wide axial ratio (AR) bandwidth by incorporating an additional dielectric substrate between the antenna and the ground plane. This is in addition to the lower feeding substrate that is located between the ground plane on one side and the feeding microstrip line on the other side. Adding another substrate on top of the ground plane provided an additional degree of freedom in the design that facilitated the achievement of ab 18% AR bandwidth. In addition, an integrated hemispherical DRA and perforated substrate configuration was utilized to achieve optimum effective substrate permittivity and overcome the DRA alignment and assembly challenges while maintaining the achieved wide CP bandwidth. A close agreement was achieved between measurements and simulations.

A Substrate Integrated Waveguide Resonator Sensor for Dual-Band Complex Permittivity Measurement

This paper presents a novel dual-band substrate integrated waveguide (SIW) sensor that is designed to measure the complex permittivities of liquids or solid powders at two industrial, scientific, and medical (ISM) frequencies simultaneously. Resonant frequencies and quality factors are obtained from S-parameter measurements with the proposed SIW sensor, and applied to reconstructing the permittivities of materials under test through an artificial neural network. The water–ethanol mixed liquids were measured with the proposed sensor. The maximum deviations of the measured permittivities at 2.45 and 5.8 GHz are within 3% of literature results. The measurement by the proposed SIW sensor with artificial neural network reconstruction is accurate and efficient.