This numerical study proposes an enhancement technique of nonreciprocal phase shift in curved composite right/left-handed metamaterial lines loaded with corrugation structures at the microstrip edges. The numerical simulation results show that the appropriately designed corrugation structures enhance the nonreciprocity.
This paper proposes a dual-polarized filtering antenna with extracted-pole unit (EPU) using LTCC substrate. The EPU realizes the high skirt characteristic of the bandpass filter with transmission zeros (TZs) located near the passband without cross coupling. The filtering antenna with EPU is designed and fabricated in 28 GHz band for 5G Band-n257 (26.5-29.5 GHz). The measured $S$11 is less than −10.6 dB in Band-n257, and the isolation between two ports for dual polarization is greater than 20.0 dB. The measured peak antenna gain is 4.0 dBi at 28.8 GHz and the gain is larger than 2.5 dBi in Band-n257. The frequency characteristics of the measured antenna gain shows the high skirt characteristic out of band, which is in good agreement with electromagnetic (EM)-simulated results.
An electromagnetic coupled type microwave heating applicator using a zeroth-order resonator (ZOR) is proposed. The guide wavelength in ZOR can be infinite regardless of the physical length, which enables uniform heating in a wide area. The characteristics of a single ZOR whose zeroth-order resonant frequency is 2.44 GHz were investigated by simulations and experiments. The heating simulation results of the thin film show the length within which the power loss density became more than 50% normalized by the maximum was 0.428λ0, where λ0 is wavelength in vacuum. This means the uniformly heatable length is successfully extended in the 1D direction.
The impedance expansion method (IEM) is a circuit modeling technique based on the method of moments. The IEM has been extended mainly for application to wireless power transfer systems. For example, the IEM has been extended to consider the presence of perfectly conducting and dielectric/magnetic scatterers. This paper introduces the basic concept, theoretical extension, and recent application of the IEM.
In this paper, new multiband Doherty power amplifier design for 5G NR Sub-6 GHz handset applications is proposed. The proposed Doherty power amplifier is demonstrated experimentally with GaAs-HBT. A PAE of 38.9% and a NR ACLR of -37.8 dBc at an average output power of 27.4 dBm are measured at 3.75 GHz under 5G NR 100 MHz, DFT-s-OFDM, QPSK operation. Moreover, the proposed Doherty power amplifier maintains more than 34.0% efficiency with a NR ACLR of below -35.6 dBc from 3.35 GHz to 5.15 GHz, corresponding to 5G NR Band n77 and Band n79.
