A triple-band stacked-patch antenna covering dedicated short-range communication (DSRC), fifth-generation (5G) millimeter-wave, and sixth-generation (6G) millimeter-wave frequency bands is reported for autonomous vehicles telematics applications. To show the effectiveness of the developed antenna, the antenna performances, such as the S-parameter, realized gain at boresight, and radiation patterns were simulated and measured for DSRC and 5G, and only simulated for 6G. The simulated results show good agreement with the measured results. The results show that the developed triple-band antenna can cover all three bands with high peak realized gains of 6.87 dBi, 12.3 dBi, and 19.8 dBi at DSRC, 5G, and 6G frequency bands, respectively, as well as high isolation between ports of >20 dB. The results also show a straightforward structure and higher antenna gain than the previously reported triple-band antennas in the simulation level.

A lossy ferrite core/dielectric shell structure effectively miniaturizes an axial-mode helical antenna (AM-HA) without sacrificing the antenna gain in the range of 2.85 to 3.45 GHz. $\rm Co_{2}Z$ hexaferrite-glass composite was used as an inner-core and acrylonitrile butadiene styrene as an outer shell. The volume of the AM-HA was reduced by 29% while maintaining realized gain of 9.0 dBic, compared to air-core AM-HA. The simulation also confirmed that further miniaturization of the AM-HA up to 43% is achievable with a slight decrease in realized gain from 9 to 8.7 dBic. The designed magnetic core/dielectric shell structure offers a vast selection of lossy ferrite for miniaturization of the AM-HA.

This paper proposes a 300 kW 24-slot/10-pole 6-phase stator-shifted fractional-slot concentrated winding spoke-type ferrite permanent magnet machine for electric truck applications. The proposed motor consists of a stator with dual three-phase windings positioned 75 degrees apart to reduce higher-order MMF harmonic order, and a rotor with an inexpensive and high-resistance ferrite permanent magnet in the spoke configuration. The simulated result of the stator-shifted machine is compared with a fabricated stator-shifted machine, and the results show good agreement with each other. To further reduce the torque ripple from 2.5 to 0.9% while maintaining a high maximum torque of 2980 Nm, circular voids with a diameter of 11 mm are embedded in the rotor. The proposed motor is evaluated for irreversible demagnetization, mechanical and thermal stability, and fault tolerant ability. To assess the proposed motor performance, the electric truck simulation model is constructed using MATLAB/Simulink and used to compare with the reported 12-slot/10-pole rare-earth permanent magnet-based machine. Compared to a previously reported six-phase rare-earth permanent magnet based flat-type machine, the proposed motor can save 4.3 kWh of energy with a USD 2512 lower cost while retaining a similar motor performance.

Along with high resistivity, W-type hexaferrite has relatively high saturation magnetization and large magnetocrystalline anisotropy, which makes it suitable for high-frequency applications. We synthesized W-type BaCo$_{1.4}$Zn$_{0.6}$Fe$_{16}$O$_{27}$ hexaferrite using a conventional solid-state reaction method. Fe precursor, α-FeOOH, was mixed with BaCO$_{3}$, Co$_{3}$O$_{4}$, and ZnO in the appropriate stoichiometric ratio, followed by firing the mixture at 950 °C for 5 h and 1300 °C for 3 h in air to obtain BaCo$_{1.4}$Zn$_{0.6}$Fe$_{16}$O$_{27}$ polycrystals. We used vibrating sample magnetometer, impedance/material analyzer, and vector network analyzer to characterize the hexaferrite for its static and dynamic magnetic properties. The ferromagnetic resonant frequency, measured from experimental permeability spectra, is in the range from 8.5 to 9.5 GHz. Its corresponding magnetocrystalline anisotropy was in the range from 10.6 to 12 kOe. This is in good agreement with the anisotropy, which was obtained from the law of approach to saturation. Spin rotation and domain wall susceptibilities were determined by fitting experimental permeability spectrum to permeability equation. Their corresponding resonant frequencies are 9.1 and 19.5 GHz for domain wall motion and spin rotation, respectively. Lastly, the figure of merits (FOM = $\mu^{\prime}/ \rm{tan}\delta_{\mu}$) of BaCo$_{1.4}$Zn$_{0.6}$Fe$_{16}$O$_{27}$ are 84 at 1 GHz ($\mu^{\prime}$ = 2.1 and tan $\delta_{\mu}$ = 0.025) and 42 ($\mu^{\prime}$ = 2.1 and tan $\delta_{\mu}$ = 0.05) at 2.2 GHz, which are the highest FOM in the frequency range from 1 to 2.2 GHz and have not been reported before.