Single-layer Substrate Integrated Waveguide Research Articles

A Compact, Single-Layer Substrate Integrated Waveguide (SIW) Cavity-Backed Active Antenna Oscillator

This letter presents the design and implementation of a single-layer, cavity-backed antenna oscillator based on substrate integrated waveguide (SIW) technology. The proposed antenna topology is particularly suitable for two-dimensional array configurations. The active circuit and the radiator are placed on opposite sides of the substrate and within the cavity area, allowing for a compact implementation. An X-band prototype was designed and fabricated, and it features frequency-tuning capability introduced by employing a varactor diode in the active circuit. The measurements showed 11.87-12.36 GHz tuning range, phase noise better than - 107 dBc/Hz at 1 MHz offset, and 7% DC-to-RF conversion efficiency.

A Multibeam Antenna Based on Substrate Integrated Waveguide Technology for MIMO Wireless Communications

A 24-beams slot array antenna, which achieves 360-degrees coverage over azimuth direction, based on substrate integrated waveguide (SIW) technology is designed, fabricated and measured for supporting the concept of triangle cell, beam diversity and multiple input multiple output (MIMO) wireless communications. Constructed by six 4-beams single layer SIW antennas which integrate the 4times8 modified Butler matrix with a low side lobe level (SLL) amplitude distribution, measured SLLs are reduced as low as -14.5 dB for all beams in E-plane. The size of the SIW single layer multibeam antenna is 385 mm times 110 mm including feeding network. The usable bandwidth of the proposed antenna is 3.75% at 16 GHz.

Substrate Integrated Waveguide Cross-Coupled Filter With Negative Coupling Structure

Substrate integrated waveguide (SIW) technology provides an attractive solution to the integration of planar and nonplanar circuits by using a planar circuit fabrication process. However, it is usually difficult to implement the negative coupling structure required for the design of compact canonical folded elliptic or quasi-elliptic cross-coupled bandpass filter on the basis of a single-layer SIW. In this paper, a special planar negative coupling scheme including a magnetic coupling post-wall iris and a balanced microstrip line with a pair of metallic via-holes is studied in detail. Two -band fourth-degree cross-coupled bandpass filters without and with source-load coupling using the negative coupling structures are then proposed and designed. The two novel SIW filters having the same center frequency of 20.5 GHz and respective passband width of 700 and 800 MHz are implemented on a single-layer Rogers RT/Duroid 5880 substrate with thickness of 0.508 mm. Measured results of those filters, which exhibit a high selectivity, and a minimum in-band insertion loss of approximately 0.9 and 1.0 dB, respectively, agree well with simulated results.