Development of a compact transverse slot array antenna using corrugation in groove gap waveguide technology

We present the proof of concept of a compact slot array antenna with proper side lobe level in groove gap waveguide (GGW) technology. Four transverse slots are etched at the GGW broad wall along with the nulls of standing TE₁₀ wave existing inside the shorted GGW. To decrease the sidelobes and antenna size, corrugations are applied through the wave path inside the GGW. Proper use of corrugations can reduce the wavelength inside the GGW leading to reduction of the distance between adjacent transverse slots, which can help to suppress the grating lobe problem and consequently enhance the radiation efficiency, which is a challenge in transvers slot array antennas. The designed antenna is optimized to achieve maximum gain, lowest grating lobe level, and return loss at 15 GHz using HFSS simulator. The achieved gain is about 13 dBi, and the SLL is better than 15 dB. To confirm the simulation results, the designed antenna was fabricated and tested. Both simulation and measurement results confirm that the grating lobes are well suppressed at the antenna operating frequency.     

Sintering behavior of Cr2AlC MAX phase synthesized by Spark plasma sintering

In the current study, the sintering and mechanical properties of the Cr₂AlC MAX phase synthesized by Spark plasma sintering at 1000, 1100, and 1200°C were investigated. The X-ray diffraction (XRD) patterns showed that the synthesis of the Cr₂AlC MAX phase was associated with the presence of impurities such as Cr₇C₃ and Al₂O₃. On the basis of the FESEM images equipped with energy dispersive spectrometer, the MAX phases had been formed successfully and the length of these layers increased by enhancing the sintering temperature. The results of the density showed that by increasing the temperature, the density increases from 5.10 to 5.33 g/cm³ and finally decreases to 5.25 g/cm³. Vickers hardness method applied to determine the hardness of the samples showed that the hardness decreases from 8.52 to 8.07 GPa for the prepared samples.