No abstract

No abstract

In this Letter, a novel empty substrate-integrated waveguide (ESIW) phase inverter (PI) applied in millimetre-wave has been proposed. ESIW PI, based on the structural symmetry design, is made of four parts: top cover, middle layer, ESIW PCB, and bottom layer. Owing to the reversed-phase transmission channel, the phase difference between the two outputs is absolutely equal to 180°. The simulation and measurement results are in a good agreement. In the entire Ka band, the return losses, insertion losses and amplitude imbalance of ESIW PI are better than 12.7, 2.66, and 0.64 dB ± 0.6 dB, respectively. Besides, the phase difference is within 180.5°± 2.9°in the same frequency band. In addition, the input and output ports are located in the identical circuit plane, which is easy to integrate with other devices and components.

In this letter, a novel 3-D empty substrate integrated waveguide (ESIW) phase shifter with equal length has been proposed. The vertical transitions have been introduced into 3-D ESIW phase shifter in the propagation path. Based on it, the different total lengths of phase shifters in the propagation path and the equal total lengths of phase shifters in the external structure are compatible. The phase shifter consists of multi-layer PCB: top layer, interlayer, middle layer, ESIW PCB, and bottom layer. The theory and design process of ESIW phase shifter have been explained and discussed in detail. To demonstrate its feasibility, the 3-D ESIW phase shifters with equal external length are designed, manufactured and measured. Final results show that the phase shifts of 45.2°±3.7° and 89.7°±4.7° can be achieved over the entire Ka-band. Besides, the return losses and the insertion losses are better than 12.5 dB, and 1.9 dB, respectively.