Dielectric rod loaded tunable substrate integrated waveguide slot antenna

Abstract

This paper presents a novel passive tuning technique to mechanically tune the resonant frequency of a substrate integrated waveguide (SIW) slot antenna, by using cylindrical rods of different dielectric materials in the air holes. A full‐wave 3‐dimensional Electromagnetic simulator software is used to estimate tunability in the resonant frequency of the SIW slot antenna, which is then analysed using its equivalent circuit, and then verified experimentally. Tunability is obtained by changing relative permittivity of dielectric rods. Measurements show good frequency tunability even with a limited number of dielectric rods and gains over 5 dBi. The similarity in the radiation patterns with tuning, demonstrates a good characteristic for tunable antennas. The technique is simple but effective and does not require external direct current bias circuitry, which removes parasitic effects and less power consumption. The low field perturbation of dielectric rods provides better loss performance and a higher Q‐factor over a wider bandwidth. The initial design demonstrates a cost‐effective tuning technique achieving return loss (>10 dB) in the X‐band. This technique is also suitable for practically overcoming the performance deviation due to fabrication inaccuracies and temperature variation.

Design of Frequency-Reconfigurable Branch-Line Crossover Using Rectangular Dielectric Channels

“…These techniques offer fast switching speeds, high-bandwidth operation, and high-quality factors, but exhibit major drawbacks such as low power-handling levels and lack of compatibility with flexible solutions required for wearable components. Therefore, liquid or solid dielectrics have been employed for the realization of tunable microwave devices [22][23][24][25][26][27][28][29][30][31][32][33][34]. Liquid dielectrics are passive and mechanically-based, highly linear, and flexible, which makes them excellent choices for high-power and wearable devices.…”

“…Recently, fluidic channels have been applied for the construction of tunable microwave filters [22][23][24][25][26][27], tunable frequency-selective surfaces [28][29], and tunable antennas [30][31][32]. In [33], a substrate-integrated waveguide (SIW) slot antenna has been designed based on a solid dielectric rod. In [34], a miniaturized SIW-based filter with frequency tunability has been designed by applying magnetized ferrite substrate.…”