Conventional power amplifiers often struggle to achieve effective impedance matching over a wide band width, resulting in increased power loss and poor harmonic suppression. In response to the requirements of modern RF communication systems for broadband and high efficiency, this paper proposes a power amplifier design scheme based on a Chebyshev low-pass filter with high and low impedance characteristics and an L-type parasitic harmonic compensation network. The design successfully suppresses high harmonics and improves frequency selectivity and impedance matching by introducing this filter. In addition, an L-type parasitic harmonic compensation network is used to extend the bandwidth and further enhance the flexibility of the impedance matching. The designed power amplifier operates in the frequency band of 0.9-1.6 GHz, centered at 1.25 GHz. Experimental results show that the gain maintains stability (>16 dB) in the lower power range and decreases significantly when the output power exceeds 20 dBm, indicating a gain compression phenomenon. The power added efficiency increases significantly once the output power exceeds 10 dBm and peaks near 30 dBm (about 60%), demonstrating high efficiency characteristics. Comprehensive experimental and simulation results validate the high performance and effectiveness of the power amplifier in the target frequency band. © 2025 IEEE.

This article proposes a method for implementing a broadband power amplifier with step impedance transformation. Based on broadband matching technology, it has good power characteristics in the range of 470MHz-860MHz through step impedance transformation. Finally, using self-developed RF-LDMOS device, a power amplifier was fabricated and tested. The test results showed that the output power reached 47dBm and the drain efficiency reached 55%, verifying the feasibility and effectiveness of the proposed scheme, which has important application value in 5G communication base stations and radar systems. © 2025 IEEE.

In order to solve the problem of reduced efficiency due to harmonic interference in multi-band power amplifiers, a dual-frequency, dual-port, high-efficiency power amplifier with harmonic suppression has been designed. A cascade design of a π-type harmonic suppression network and a multi-branch single-frequency matching network has been proposed. This design suppresses the harmonics generated by each branch under the condition of realizing multi-frequency and multi-channel. It improves the amplifier's efficiency and does not have an impact on the subsequent fundamental matching. The efficiency of the amplifier is enhanced, and it does not impact the subsequent fundamental matching. In order to verify the experiment's feasibility, the designed power amplifier was simulated and tested. The electromagnetic simulation results indicate that the output power at 0.9 GHz and 2.4 GHz is 40.5 dBm and 40.3 dBm, respectively. The drain efficiency is 69% and 68.3%, the gain is 11.5 dB and 10.8 dB, and the difference in the second and third harmonics power fundamental power is -48 dBm and above. © 2025 IEEE.

In this paper, a wide-band and compact MIMO antenna is proposed, which achieves a bandwidth of 5.6-19GHz and an antenna size of 18×34mm2. In order to improve the isolation, rectangular slots are cut off in the T-shaped structure of the ground layer to form two inverted L-shaped structures. The inverted U-slit was etched on the feeder, the C-slit was etched on the radiating patch, and the T-branch was added to the inner side of the feeder to obtain the trapping characteristics of C band uplink frequency(5.925-6.425GHz), ITU(8.01-8.5GHz) and Ku broadcast frequency(17.3-17.8GHz), respectively. The S-parameters, isolation, ECC, realized gain and radiation efficiency of the antenna are analyzed by simulation and measurement results. S21 © 2024 Copyright held by the owner/author(s).

In this paper, a high efficient ultra-wideband balanced power amplifier (PA) employing a multi-frequency point harmonic control network is proposed. Using the multi-frequency point harmonic control method to realize the harmonic matching network not only makes the matching impedance points fall into the appropriate impedance region but also effectively broadens the bandwidth of the power amplifier. To verify the proposed method, a balanced high-efficiency ultra-wideband PA is designed using GaN devices based on the broad impedance matching design space of the ECCB/J power amplifier mode. The simulation results show that the saturated output power is higher than 40 dBm, the gain is more than 9.4 dB, the drain efficiency is maintained above 60% in the frequency range of 0.7~2.5 Hz, and the maximum drain efficiency is up to 71%. © 2025 IEEE.

This study designed experimentally a compact single-band notch ultra-wideband (UWB) multi-input and multioutput (multiple-input multiple-output, or MIMO) antenna with good isolation. The enhanced ground surface and two microstrip feeders positioned next to each other on a FR-4 substrate measuring 31 mm, 46 mm, and 0.8 mm together make up the small antenna. Realize the broadband and increase the antenna's low frequency bandwidth by slicing the bottom of the radiation patch. In order to maximize the antenna's primary radiation direction and increase its high frequency bandwidth, the patch uses a trapezoidal construction. In order to minimize antenna coupling and attain a high degree of isolation, the upgraded Tshaped and rectangular groove decoupling structures are loaded on the connecting floor simultaneously. To reject probable 5G interference, the U-shape slot can acquire a notch band with band rejection of 4.71-5.08GHz. According to the simulation and test results, it can operate within the desired UWB frequency band between 2.81 and 14GHz (the relative bandwidth reaches 200%). The isolation degree of the entire working bandwidth is greater than 22dB, the envelope correlation coefficient (ECC) is less than 0.01 with a stable gain and good radiation efficiency (above 50%), and the total active reflection coefficient (TARC) attribute is relatively stable, making it appropriate for the UWB MIMO system in use. © 2024 IEEE.

In recent years, there has been a tremendous interest in military individual radio in wireless communication. To obtain sufficient operating distance and long standby time, the output power and efficiency of power amplifiers have become the research focus by some of the research teams. GaN has higher electron mobility and forbidden bandwidth than other materials. Nowadays, GaN has become the mainstream key technology for radio frequency (RF) power amplifiers in 5G communication systems. In this work, a 500MHz~2500MHz GaN-based HEMT wideband cascaded power amplifier was designed. The output power of the driver amplifier is 36.6dBm ± 0.5dB, the input return loss is 20%, the DC power consumption is 10 dB, input voltage standing wave ratio © 2024 IEEE.

This paper designs a miniaturized K-band Multiple Input Multiple Output (MIMO) antenna based on DGS, with an overall size of only 15 mm× 24 mm× 1.2 mm. The front of the antenna is composed of a circular radiating patch combined with a trapezoidal microstrip feed line, achieving K-band operation on the basis of antenna miniaturization. The back features a Defected Ground Structure (DGS), with two semi-circular notches etched at the top of the ground plane, which achieves low coupling characteristics for the antenna. The antenna is simulated and measured using three-dimensional electromagnetic simulation software and a vector network analyzer, respectively. The results show that the antenna operates over a bandwidth of 17.98-28 GHz (achieving a relative bandwidth of 43.6%). Additionally, the coupling level remains less than -16 dB throughout the entire operating frequency range. The Envelope Correlation Coefficient (ECC) is less than 0.006. Thus, the designed antenna is not only extremely small and structurally simple, but also performs well, making it widely applicable in wireless communication systems. © 2024 IEEE.

The MEMS torsional mirror is an important MEMS optical device, and its related applications are very wide, including LiDAR, projection equipment, optical communication, and so on. At present, the electrostatically driven MEMS torsional mirror mainly adopts a vertical comb driver to achieve torsional motion, which has some disadvantages such as a complicated manufacturing process, low yield, and high driving voltage. In this paper, a novel MEMS torsional mirror structure is proposed, which provides flexible elastic constraint points for the torsional mirror with the bottom support rod structure as the center, and relies on the combination of planar comb and support rod to form a tie rod structure to achieve torsion, and achieves a torsion Angle of ±15.55° under the driving voltage of 65 V. The use of a planar comb instead of a vertical comb greatly reduces the difficulty of manufacturing. Finally, it is verified that the system stability is good, the correlation drift does not affect the results within the range, the fifth-order modes are within the reasonable range, and the maximum stress is 671 MPa, which is controlled within the range of fracture stress of silicon material. © 2024 Institute of Physics Publishing. All rights reserved.

In order to solve the problem that the ultra-wideband system has a wide passband and is susceptible to other signal interference, a miniaturized three-notch ultra-wideband filter was proposed. The triple notch characteristic is achieved by asymmetric coupling techniques and the loading of two resonators on an ultra-wideband filter. The passband of the UWB filter is 3.0 - 12.3GHz, the relative bandwidth is 121.6%, and three notches are generated at 5GHz, 7.5GHz and 9.7GHz, respectively, and the notch depths are 26.7dB, 24.5 dB and 20 dB, respectively, which can avoid the interference of 5G frequency band, C band and X communication frequency band to UWB system. The size of the filter is only 18.04× 5mm, which meets the needs of miniaturization, and the center frequency is 6.85GHz, and the out-of-band rejection effect is good. © 2024 IEEE.