The unprecedented development of substrate integrated circuits (SICs) has made a widespread necessity for further studies and development of waveguides and antennas based on this technology. As the operating frequency is on the rise, the conventional designs of the substrate integrated components are becoming more problematic and costly. Therefore, some techniques are proposed to improve the performance of the waveguides and antennas based on the concept of substrate integrated technology.
First, the problems of the recently developed ridge gap waveguide (RGW) are resolved by introducing a new configuration of this technology which has considerable advantages over the original version of the RGW regarding its construction technology, propagation mode, characteristic impedance, and insertion loss. Second, the configuration of substrate integrated waveguide (SIW), which has been widely accepted for planar and integrated microwave circuits, is modified to operate with low insertion loss at high frequencies without bearing the anisotropic nature of the dielectric material.
The substrate integrated antennas have a strong potential to be used in the compact wireless devices as they can be easily integrated with the baseband circuits. In the horn family, the H-plane horn antenna that can be implemented in the integrated form has received considerable attention in recent years. However, numerous problems are associated with this antenna such as limited bandwidth, tapered aperture distribution, high back radiation, and E-plane asymmetry. Several new techniques are introduced to improve the performance of this antenna, especially at millimeter wave frequencies
