PIER C | PIER Journals

2024-09-23

PIER C

Vol. 147, 167-173, 2024

download: 43

Obtaining Low Sidelobe Level and Reduced Complexity in Linear and Planar Antenna Arrays Using Thinned Subarrays

Ahmed Jameel Abdulqader , Jafar Ramadhan Mohammed and Yessar Ezzaldeen Mohammed Ali

Conventionally, the thinning process in antenna arrays was performed at the element level with random selection after examining all the possible combinations. Thus, the computational time of such thinned methods was relatively high. Reducing the undesirable high computational time is of great interest. In this paper, the thinning process is performed at subarray level rather than element level, thus, the computational time and array complexity were significantly reduced while minimizing the peak side lobe level (PSLL). The optimization process consists of two steps where in the first step the array elements are portioned into a number of nonuniform ascending subarrays, while in the second step some of the least significant subarrays were turned off. Moreover, two schemes were used to portion the array elements. The first one is based on portioning all the array elements into ascending subarrays. This is known as fully nonuniform ascending subarray configuration since the entire array elements were portioned into smaller unequal groups. The second one is based on portioning only part of the elements located at the sides of the array, while leaving the central elements individually without any partition. This is known as partially nonuniform ascending subarray configuration. The genetic optimization algorithm is used to find out optimally which subarrays need to be thinned (or turned off) by setting their excitation amplitudes to zero. The simulation results for a total of 100 elements linear array illustrate that the PSLL, in the full subarray configuration, can be minimized to more than -33 dB by thinning 5 subarrays and the complexity reduction percentage was 72% before thinning and it becomes 82% after thinning. On the other hand, the PSLL in the partial subarray configuration was reduced down to more than -30 dB by thinning 4 subarrays at each side of the array. In this case. The complexity reduction percentage was 52% before thinning, and it becomes 60% after thinning. The number of individual central-elements on both sides of the array was 26, and the number of subarrays on both sides of the array was 22. Furthermore, the idea of the thinned subarrays was successfully extended and applied to the two-dimensional planar arrays of 100 × 100 elements.

Obtaining Low Sidelobe Level and Reduced Complexity in Linear and Planar Antenna Arrays Using Thinned Subarrays

2024-09-08

PIER C

Vol. 147, 161-166, 2024

doi:10.2528/PIERC24070305

download: 96

A Planar Five-Section Short-Length Coupled-Line Band-Stop Filter with Two Reconfigured States

Mengxin He , Xiaoying Zuo , Hang Mei and Yajian Li

A novel circuit structure is proposed to design a small size band-stop filter. The structure consists of five pairs of short coupled-lines. The bandwidth, roll off and center frequency of the filter can be flexibly controlled by changing the data of different pairs of coupled-lines. By disconnecting the left-most pair of coupled-lines, the band-stop filter can be transformed into a full resistance filter. The center frequency of the band-stop filter is 2.40 GHz. The measured 20-dB stopband insertion loss bandwidth is 29.2% (2.05-2.75 GHz, the highest measured rejection is 44.21 dB). The simulation results agree well with the measured ones, which verifies the effectiveness of the proposed structure. The use of coupled-lines makes the structure more compact. The circuit size is 0.35λ_g × 0.27λ_g (25.63 mm × 19.70 mm).

A Planar Five-section Short-length Coupled-line Band-stop Filter with Two Reconfigured States

2024-09-08

PIER C

Vol. 147, 153-159, 2024

doi:10.2528/PIERC24072903

download: 444

Reconfigurable SIW-Based Bandpass Filter Using Open Ring Resonators for Ku/k -Band Application

Ruchi Paliwal , Shweta Srivastava and Reema Budhiraja

This manuscript introduces an advanced architecture for a reconfigurable band-pass filter, utilizing substrate-integrated waveguide (SIW) technology. To induce a transmission zero in the passband response of the filter, the design involves coupling two identical open-loop ring resonators in a back-to-back configuration on top of the SIW cavity. The work includes a comprehensive investigation of the variation in notch frequency with respect to the ring diameter. Further incorporating PIN diodes into the structure enabled the realization of a reconfigurable filter that can be switched between a broad passband and two narrow passbands with a notch. Also, a planar DC biasing network has been specifically designed to bias the diodes. Additionally, a prototype has been developed to validate the concept and the performance in terms of reflection and transmission coefficients. The miniaturized reconfigurable filter design presented is well suited for the use in both Ku- and K-band applications due to its specific performance characteristics.

Reconfigurable SIW-based Bandpass Filter Using Open Ring Resonators for Ku/K-band Application

2024-09-06

PIER C

Vol. 147, 145-152, 2024

doi:10.2528/PIERC24070601

download: 178

Calculation and Analysis of Eddy Current Loss in High Temperature Permanent Magnet Canned Motor

Quanfeng Li , Ziwei Wang and Xiang Li

As an important part of the primary circuit system of a nuclear power plant, the safe and stable operation of the canned motor of a nuclear main pump is crucial. The existence of stator can and rotor can in the air gap of a canned motor will generate additional eddy current loss during the operation of the motor, which will be detrimental to the long-term stable operation of the motor. Therefore, in this paper, in order to analyze and weaken the eddy current loss generated on the shielding can, using the empirical formula method, the eddy current loss generated by the shielding can before optimization is calculated, and the relationship among the eddy current loss, can thickness, and motor speed is derived. Subsequently, two shielding can structure optimization schemes were proposed, and the reduction of eddy current loss after optimization was calculated using finite element simulation software. The effects of different optimization schemes were compared. Finally, peak torque and current experiments are conducted on the original motor to verify the accuracy of the finite element calculation results. The results show that both optimization schemes proposed in this paper can reduce the eddy current loss, and the axial segmentation scheme has a better reduction effect on the shielding can.

Calculation and Analysis of Eddy Current Loss in High Temperature Permanent Magnet Canned Motor

2024-09-03

PIER C

Vol. 147, 135-144, 2024

doi:10.2528/PIERC24062004

download: 103

SAR Target Recognition Based on Multi-View Differential Feature Fusion Network Under Small Sample Conditions

Yuxin Ma , Benyuan Lv , Jianfei Ren , Yun Guo , Jiacheng Ni and Ying Luo

Deep learning network has the advantages of strong learning ability, strong adaptability, and good portability. Therefore, synthetic aperture radar (SAR) automatic target recognition (ATR) based on deep network is widely used in both military and civilian fields. However, due to the imaging conditions, radar angle, imaging distance, and other reasons, it is difficult to obtain efficient and usable SAR image datasets. SAR images' recognition under small sample conditions is still a challenging problem. In this paper, a SAR target recognition method based on multi-view differential feature fusion network is proposed to address this problem. Considering the correspondence between RCS and target features, the network extracts dissimilarities between features from SAR images of different angles of the same target and fuses them with the original features of one angle to form new features, which enriches the available training data. Experimental results on the Moving and Stationary Target Acquisition and Recognition (MSTAR) public dataset show that the proposed method has a higher target recognition rate than other deep network methods, as well as single angle input recognition methods.

SAR Target Recognition Based on Multi-view Differential Feature Fusion Network under Small Sample Conditions

2024-09-03

PIER C

Vol. 147, 127-134, 2024

doi:10.2528/PIERC24063002

download: 144

Factorial Analysis on the Preparation of Barium Titanate-Epoxy Resin Composite for Antenna Substrate

Nur Sofia Idayu Didik Aprianto , Nurulfadzilah Hasan , Nurul Izzah Izzaty Mohd Nadzri , Nurfarhana Mustafa , Loh Fui Qi , Ahmad Afif Mohd Faudzi , Nurhafizah Abu Talip Yusof and Mohamad Shaiful Abdul Karim

This study investigates the preparation and characterization of barium titanate-epoxy resin composites, focusing on main factors influencing the dielectric properties of that composite materials. Using a 2^k fractional factorial design, the effects of heating temperature, stirring speed, stirring time, and hardening process on the permittivity were thoroughly investigated. Sixteen samples were prepared and analyzed using Design-Expert software, with permittivity measurements conducted via the waveguide method and a Vector Network Analyzer (VNA) in the 4-6 GHz range. Results show significant impacts from stirring time and speed, with optimal conditions identified as 50°C heating, 500 rpm stirring speed, three minutes stirring time, and room temperature hardening from two-level factorial analysis (TLFA). These findings provide valuable insights into the best fabrication conditions for barium titanite-epoxy resin composites, contributing to the development of antenna substrate with a permittivity value of 7.0208 and a loss tangent of 0.0238 that is suitable for high-frequency communication applications.

Factorial Analysis on the Preparation of Barium Titanate-epoxy Resin Composite for Antenna Substrate

2024-09-01

PIER C

Vol. 147, 117-125, 2024

doi:10.2528/PIERC24071512

download: 132

Maximum Efficiency Tracking of Underwater Wireless Power Transmission System Based on Dynamic Coupling Coefficient Estimation

Zhongjiu Zheng , Yanpeng Ma , Xingfeng Cao , Zhilong Wu and Jinjun Bai

For the complex marine environment, the water flow disturbance causes the receiver offset, which leads to the decrease of mutual inductance and the decrease of system efficiency. This paper proposes an estimation method of dynamic coupling coefficient without communication, and further realizes the maximum efficiency point tracking (MEPT) on the receiving side. By collecting the effective value of the fundamental current on the receiving side, the equivalent impedance mode equation of mutual inductance is established, and the mutual inductance is identified in real time by numerical solution method. On the basis of the identification results, the impedance matching is realized by the closed-loop controller designed on the receiving side, and the maximum efficiency point tracking of the system is realized. In this paper, the experimental platform is built, and the effectiveness of the method is verified by experiments. The experimental results show that the accuracy of mutual inductance estimation is more than 95%, and the efficiency of the system is improved by 18% after using the maximum efficiency point tracking.

Maximum Efficiency Tracking of Underwater Wireless Power Transmission System Based on Dynamic Coupling Coefficient Estimation

2024-08-30

PIER C

Vol. 147, 109-116, 2024

doi:10.2528/PIERC24061905

download: 127

Stator Winding Interturn Short-Circuit Fault Detection in WRIM Using Rise and Fall Times of Stator Currents

Habachi Bilal , Svetlana Dyagileva , Nicolas Heraud , Eric Jean Roy Sambatra and Blaise Ravelo

One of the major challenges of today's rotating machine manufacturing industries is finding effective techniques to prevent early mechanical or electrical failure. Efficient troubleshooting methods must be developed for rotating electrical machines, such as three-phase and multiphase electrical induction or synchronous machines. A novel method for fault detection in a Wound Rotor Induction Machine (WRIM) is presented in this paper. Its originality lies in the determination of current rise and fall times in healthy and InterTurn short-Circuit Fault (ITSCF) cases. The method is based on using the two-current (i_sd, i_sq) sigmoid transform (ST) of Park's vector approach. A WRIM with a nominal power of 0.3 kW is used for the analytical and experimental studies. The type of fault detection being studied is short circuit InterTurns on one phase of the stator winding. The results are promising because the methodology used is simple, fast, and accurate for diagnosing this type of fault, and can detect a low number of short-circuit InterTurns in the stator winding.

Stator Winding InterTurn Short-circuit Fault Detection in WRIM Using Rise and Fall Times of Stator Currents

2024-08-27

PIER C

Vol. 147, 99-107, 2024

doi:10.2528/PIERC24071301

download: 125

A Novel Bandpass-to-All-Stop Switchable Absorptive Filter with Ultra-Wideband Reflectionless Range

Bingjie Yang , Zhongbao Wang , Shipeng Zhao , Hongmei Liu , Mingming Gao and Shao-Jun Fang

A novel bandpass-to-all-stop switchable absorptive filter with an ultra-wideband reflectionless range is proposed in this paper. The bandpass section of the filter consists of a dual-mode resonator and two L-shaped feeding lines. The dual-port reflectionless characteristic is achieved by loading absorption networks at the end of the open stubs of the feeding lines, which are composed of two parallel coupled lines and absorption resistors. The switching of the reflectionless bandpass filter (RBPF) to the all-stop filter (ASF) is realized by controlling the on/off behavior of the PIN diode through the bias voltage. Measurements show that the filter prototype at the center frequency of 2.43 GHz with the 3-dB fractional bandwidth (FBW) is 8.23%. For the RBPF state, the filter has an ultra-wideband reflectionless FBW of 214% and upper stopband rejection better than 33 dB up to 6 GHz. Besides, the rejection is better than 30 dB from 0 to 5.32 GHz in the ASF state.

A Novel Bandpass-to-all-stop Switchable Absorptive Filter with Ultra-wideband Reflectionless Range

2024-08-26

PIER C

Vol. 147, 89-97, 2024

doi:10.2528/PIERC24061102

download: 184

Linear-to-Circular Polarization Conversion Metasurfaces with Multibeam for Ka-Band Satellite Applications

Jinfeng He , Honggang Hao , Ting Zhang , Dan Yin and Zhilin Zou

In this paper, a transmissive linear-to-circular polarization conversion (LCPC) multibeam metasurface is presented, which shows promise for point-to-multipoint transmission in satellite communications under interference conditions. The unit cell consists of four identical metal layers and three dielectric substrates, where each metal layer includes a square ring and a cross-shaped structure. By altering the arm length of the cross-shaped structure, independent control of the phase of x- and y-polarized waves can be achieved. Thus, by keeping the amplitude of the x- and y-polarized waves equal and the phase difference at 90˚, LCPC is realized. Based on the multibeam superposition theorem, the metasurface array is arranged using four discrete elements with a phase gradient of 90˚. It can convert linearly polarized (LP) waves into right-handed circularly polarized (RHCP) waves and generate transmitted multibeam at predetermined angles and gain ratios. Three-beam LCPC metasurfaces with equal and unequal gain in the Ka-band (26 to 40 GHz) were demonstrated to validate the proposed unit cell and methods. The equal gain metasurface has an approximate 11% bandwidth for the 3 dB axial ratio (AR) and a 12% bandwidth for the 3 dB gain. Furthermore, at the center frequency of 30 GHz, the unequal gain metasurface achieves gains of 22.9 dBi, 19.7 dBi, and 17.3 dBi, respectively, with an AR of less than 2 dB for all three beams.

Linear-to-circular Polarization Conversion Metasurfaces with Multibeam for Ka-band Satellite Applications

2024-08-26

PIER C

Vol. 147, 81-87, 2024

doi:10.2528/PIERC24061705

download: 112

Novel Compact UWB Antenna Design with Notch Filter Characteristics: Development and Performance Enhancement

Ujjval Dave , Shahidmohammed Modasiya , Abhinav Dave and Rahulkumar Patel

This paper introduces a novel compact microstrip-fed ultra-wideband (UWB) antenna, characterized by its unique square patch design and integrated parasitic circular patch for frequency band rejection. The antenna, fabricated on an FR4 substrate, exhibits dimensions of 0.17λ_g × 0.17λ_g, optimizing space without compromising performance. A significant innovation of this design is the incorporation of a parasitic circular patch with a meticulously optimized radius of 0.02 × λ_g mm, achieving a remarkable return loss of -43 dB at 3.55 GHz, while frequencies ranging from 5.43 to 7.1 GHz exhibit significant notching. This feature effectively eliminates unwanted frequency bands, enhancing the antenna's application in UWB systems. Comprehensive analysis demonstrates that the antenna maintains an omnidirectional radiation pattern and achieves a desirable gain, making it highly compatible with a variety of UWB-enabled devices. The integration of the parasitic circular patch within the compact design not only improves the antenna's spectral purity but also contributes to its practical applicability in modern wireless communication systems. The findings underscore the potential of this antenna design in advancing UWB technology applications, offering a balance among compactness, efficiency, and performance.

Novel Compact UWB Antenna Design with Notch Filter Characteristics: Development and Performance Enhancement

2024-08-26

PIER C

Vol. 147, 73-79, 2024

doi:10.2528/PIERC24072406

download: 84

Design of a Reconfigurable Multi-Band Antenna with Partially Dredged Cloverleaf

Tao Tang , Jiawei Wang , Melad M. Olaimat , Tao Fang and Xiexun Zhang

This paper presents a novel reconfigurable multi-band antenna with a partially dredged cloverleaf shape that is tailored for size reduction and suitable for compact devices and urban environments. The antenna is capable of covering three distinct frequency bands: 3.22-4.06 GHz, 4.44-6.12 GHz, and 3.8-4.77 GHz, with respective bandwidths of 22%, 31.8%, and 22.6%, demonstrating its wideband capabilities. Utilizing various feeding configurations, the antenna enables the realization of multiple radiation patterns and frequency tuning. Validated through simulations and measurements, this design shows promise for 5G and advanced communication systems.

Design of a Reconfigurable Multi-band Antenna with Partially Dredged Cloverleaf

2024-08-24

PIER C

Vol. 147, 65-72, 2024

doi:10.2528/PIERC24042504

download: 149

A Planar Quad-Band Bandpass Filter Employing Transmission Lines Loaded with Tri-Stepped Impedance Open- and Dual-Stepped Impedance Short-Ended Resonators

Kamran Arif , Kanaparthi V. Phani Kumar , Rusan Kumar Barik and Geetha Chakaravarthi

A highly miniaturized bandpass filter with quad-band response is demonstrated in this article. The proposed quad-band bandpass filter has a novel topology comprising series quarter wavelength transmission lines loaded with tri stepped impedance open-ended resonators and a dual stepped impedance short-ended resonator. The proposed quad-band bandpass filter configuration is validated by theoretically verifying the transmission zeros and poles frequencies using even-odd mode analysis. A prototype operating at 0.47 GHz, 1.68 GHz, 3.47 GHz, and 4.51 GHz is designed, implemented, and experimented. The tested insertion losses at these center frequencies are 0.38 dB, 0.71 dB, 1.03 dB, and 1.22 dB, and the return loss is better than 10 dB in each passband. Each passband is isolated by a transmission zero with a rejection better than 40 dB. The proposed quad-band filter occupies a compact size of 0.146 × 0.087λ_g2 and is distinguished by its high compactness, wide bandwidth, multiple transmission zeros and poles, and high performance compared to benchmark designs making it more suitable for multi-band wireless applications.

A Planar Quad-band Bandpass Filter Employing Transmission Lines Loaded with Tri-stepped Impedance Open- and Dual-stepped Impedance Short-ended Resonators

2024-08-24

PIER C

Vol. 147, 55-63, 2024

doi:10.2528/PIERC24070301

download: 81

Compact Wideband Wide-Beam Circularly Polarized Loop Antenna Using Sequential Rotation Feeding Technology

Sihan Liu , Hongmei Liu , Youjie Zeng , Yanjie Pei and Zhongbao Wang

In this paper, a wideband wide-beam circularly polarized (CP) antenna excited by sequential rotation feeding technology is proposed. The antenna is primarily constituted of a loop radiating element and a reactive impedance structure (RIS) cavity. The loop radiator is stimulated by a curved feeding line through six slots etched on the ground, thereby enabling the antenna to achieve broadband performance. In order to achieve a wide 3-dB axial-ratio beamwidth (ARBW), as well as exhibit less effect on the half-power beamwidth (HPBW), a RIS cavity is introduced beneath the loop radiator. To validate the proposed structure, a prototype was constructed and subjected to a series of tests. The results indicate that the bandwidth of the antenna is 187.5% (0.11~3.41 GHz) under a 10-dB return loss. In the frequency band spanning from 1.07 GHz to 2.1 GHz, the AR is less than 3 dB, yielding a bandwidth of 64.98%. Furthermore, at the frequencies of 1.2 GHz, 1.5 GHz, and 1.8 GHz, the proposed antenna demonstrates wide beam characteristics, with the HPBW exceeding 90°, and the 3-dB ARBW within 162°- 224°. In addition, since no extra feeding network is utilized, the antenna is compact in size.

Compact Wideband Wide-beam Circularly Polarized Loop Antenna Using Sequential Rotation Feeding Technology

2024-08-23

PIER C

Vol. 147, 45-53, 2024

doi:10.2528/PIERC24052404

download: 109

Design and Electromagnetic Performance Investigation of a Compact Pneumatic Drive Linear Generator Used in Wave Energy Conversion

Yusheng Hu , Chouwei Guo , Mengyuan Niu and Lijin He

Ocean wave energy is an inexhaustible clean new energy resource, and wave direct-drive linear generator is an energy converter receiving wide attention, but it suffers from the deficiencies of difficult energy harvesting, slow movement speed, large size, and small power generation, etc., so there is an urgent requirement to develop high-efficiency small-scale energy conversion devices. In this paper, a pneumatic drive linear generator (PDLG) is provided as a high efficient compact wave energy converter (WEC). The structure design and automatic reciprocating control system for the PDLG are implemented. The field distribution characteristics and parameters effects are analyzed using the finite-element method based on scalar magnetic potential. Finally, a prototype was fabricated to verify the performance of the PDLG. The experimental results are in good agreement with that of the theoretical prediction. The results of the study show that the provided pneumatic drive linear generator can meet the requirements of high efficient wave energy harvesting, compact structure, and larger power generation.

Design and Electromagnetic Performance Investigation of a Compact Pneumatic Drive Linear Generator Used in Wave Energy Conversion

2024-08-23

PIER C

Vol. 147, 39-44, 2024

doi:10.2528/PIERC24070502

download: 80

Wideband Unequal Four-Way Filtering Power Divider with Absorptive Feature

Shuyi Chen , Hongmei Liu , Teng Ma and Zhongbao Wang

In the paper, a wideband four-way filtering power divider with arbitrary power division ratio and input absorptive feature is proposed. Two sets of coupled lines (CLs) are used to achieve the wideband performance. To obtain absorptive properties, a set of T-type absorption structure consisting of two isolation resistors and a λ/4 short-circuit stub is connected between the two CLs. Meanwhile, high frequency selectivity and good out-of-band rejection are realized by introducing two stepped-impedance resonators. Besides, output impedance matching, isolation and unequal power distribution are achieved by the power division section in the second stage. In the analysis, the equations are derived by using the method of even-odd mode decomposition and voltage-current method. For demonstration, a prototype is designed, fabricated, and measured with the power distribution ratio of 2:1:1:2. Measurements show that an all-frequency band absorption of 200% is obtained with the 3-dB passband bandwidth of 78.1% and the out-of-band rejection of 14 dB. Besides, it also shows 15-dB isolations within more than 60% FBW, and has the feature of small size.

Wideband Unequal Four-way Filtering Power Divider with Absorptive Feature

2024-08-22

PIER C

Vol. 147, 27-37, 2024

doi:10.2528/PIERC24061002

download: 136

Nonlinear Testing-Based EMI Characterization of Wireless Communication Transmitter with Microwave Power Amplifier

Hongyu Du , Fayu Wan , Vladimir Mordachev , Eugene Sinkevich , Xiaohe Chen , Glauco Fontgalland , Dinh-Thuan Do , Samuel Ngoho and Blaise Ravelo

An effective empirical method of EMI analysis for transceiver (Tx-Rx) system implemented with nonlinear (NL) microwave power amplifier (MPA) dedicated to wireless communication is developed. The nonlinearity is experimentally quantified by the MPA gain, P1dB and third order intermodulation component via spectral response around 2.4 GHz 802.11b IEEE frequency band. The proof-of-concept represents the Tx-Rx system environment for wireless communication. The considered test signal emulates synchronization and physical broadcast different channels of downlink communication signals under QPSK modulation. The error vector magnitude (EVM) and signal-to-noise-ratio (SNR) due to the microwave Tx-Rx transmission undesirable EMI effect are assessed. Without MPA, the EVM and SNR of various channels fluctuate within a small range. Because of MPA nonlinearity, EMI becomes awfully significant due to the intermodulation generating SNR 20-dB decrease.

Nonlinear Testing-based EMI Characterization of Wireless Communication Transmitter with Microwave Power Amplifier

2024-08-22

PIER C

Vol. 147, 15-25, 2024

doi:10.2528/PIERC24071203

download: 159

Sickle-Shaped Tri-Band MIMO Antenna for 5G and X-Band Applications

Yiwei Tao , Han Lin , Ming Yang , Wenyan Nie , Chenlu Li and Mingqing Wang

This paper presents a compact, highly isolated tri-band MIMO antenna for 5G and X-band communication applications. The overall dimensions of the antenna are 43 mm × 30 mm × 1.6 mm. It consists of two monopole radiating units and a metal base with branches and slit slots. The antenna achieves tri-band characteristics by improving the shape of the radiating patch. The isolation of the antenna is enhanced by slotting the floor and loading I- and T-shaped branches to absorb coupling currents. S₁₂ > 15 dB is achieved in the frequency ranges of 3.3 GHz-4.06 GHz, 4.62 GHz-5.28 GHz, and 8.14 GHz-9.28 GHz. Measurement results show that the measured S-parameters do not change significantly compared with the simulation. It also has a low envelope correlation coefficient and good radiation performance.

Sickle-shaped Tri-band MIMO Antenna for 5G and X-band Applications

2024-08-22

PIER C

Vol. 147, 9-13, 2024

doi:10.2528/PIERC24052006

download: 100

Dual Higher-Order Orbital Angular Momentum Antenna Based on Rectangular Waveguide

Na Li , Lingling Jiao , Guirong Feng , Ping Li and Xiao-Wei Shi

This paper proposes an antenna based on a rectangular waveguide to generate dual higher-order orbital angular momentum (OAM) beams. The OAM beams with modes l = -6 and l = -7 are produced by radiating the higher order TE_mn transmitted in the rectangular waveguide through a slot. The measurement results indicate that the impedance bandwidth of less than -10 dB is approximately 37.8% in the range of 15-22 GHz, and the mode purity of the antenna is above 55%. The proposed antenna feed structure is simple and does not require a complex phase-shifting network to generate multi-mode and higher-order OAM beams. Such an OAM-based antenna with dual higher-order OAM beams can be utilized in MIMO-OAM communication systems, radar imaging systems, and rotational speed measurement systems.

Dual Higher-order Orbital Angular Momentum Antenna Based on Rectangular Waveguide

2024-08-20

PIER C

Vol. 147, 1-8, 2024

doi:10.2528/PIERC24053001

download: 107

A Novel Interference Suppression Algorithm Based on Analog Circuits Preprocessing

Xiaolei Sun , Chunteng Li , Guangming Li and Juan Chu

Aiming at two problems of the low radiation efficiency of the transmitted antennas and facing strong interference in extremely-low-frequency (ELF) communication, a new structure of a receiving array is proposed, and the signal preprocessing scheme in the receiver front-end is designed, which can suppress 50Hz interference and its harmonic components effectively, thereby enhancing the detective ability on the weak desired signal. In order to suppress the interference within signal bandwidth, a novel improved generalized sidelobe cancellation algorithm (IGSCA) is proposed. By combining with the proposed receiving array structure, the problem on the desired signal radiated into the reference antennas has been addressed effectively. In order to test the proposed algorithm's performance, an experimental platform is set up under the laboratory environment, mainly adopting a data acquisition unit named NI 9184. The results show that the proposed algorithm can improve the better signal-to-noise-plus-interference ratio (SINR) to a great extent, and the more the number of reference antennas is, the higher the improved performance is.