PIER Letters | PIER Journals

2024-11-20

PIER Letters

Vol. 123, 77-82, 2025

download: 20

Miniaturized Coplanar Waveguide to Rectangular Waveguide Transition Using Integrated Resonators and Variable Housing

Ting-Tzu Cho and Chun-Long Wang

In this paper, a miniaturized coplanar waveguide (CPW) to rectangular waveguide (RGW) transition using integrated resonators and variable housing is proposed. By properly designing the dimensions of the integrated resonators and variable housing, a compact and broadband transition can be accomplished. The -15-dB fractional bandwidth of the transition is as broad as 45.2%, which ranges from 8.21 GHz to 13 GHz, covering the whole X-band (8.2-12.4 GHz). Besides, the transition size is as small as 3.94 mm. To reduce the mechanical complexity, the housing height is from 24.5 mm to 22.86 mm, which is equal to the height of the rectangular waveguide. The -15-dB fractional bandwidth of the transition is as broad as 45.5%, which ranges from 8.18 GHz to 13 GHz, encompassing the whole X-band. Besides, the transition size is still as small as 3.94 mm. To verify the simulations, a back-to-back CPW-to-RWG transition is fabricated and measured. The simulation and measurement results are in good agreement.

Miniaturized Coplanar Waveguide to Rectangular Waveguide Transition Using Integrated Resonators and Variable Housing

2024-11-19

PIER Letters

Vol. 123, 69-76, 2025

doi:10.2528/PIERL24090403

download: 37

A Large-Frequency-Ratio Filtering Crossover Based on Ridged SIW Resonators

Tianle Zhou , Yuchen Yin , Wei Shen , Zixuan Yi and Tao Zhao

A novel filtering crossover featuring flexibly allocated center frequencies based on ridged substrate integrated waveguide (RSIW) is proposed. Two TE₁₀₁-mode SIW cavities, two loading single ridge SIW (SRSIW) cavities and a loading triple ridge SIW (TRSIW) cavity are used to realize the filtering crossover. Good transmission and isolation responses can be achieved based on orthogonal degenerate TE₁₀₂ and TE₂₀₁ modes in the centered TRSIW cavity. The frequency ratio of the TE₁₀₂ and TE₂₀₁ modes can be significantly improved by adjusting the aspect ratio and the dimensions of ridges in the centered TRSIW cavity. A prototype operating at 4.98 GHz/10.1 GHz is fabricated and measured. The measured results demonstrate excellent agreement with the simulated one.

A Large-frequency-ratio Filtering Crossover Based on Ridged SIW Resonators

2024-11-10

PIER Letters

Vol. 123, 61-67, 2025

doi:10.2528/PIERL24100307

download: 78

Adaptive Dual-Band Antenna for 5G and Its Applications with Monopole-to-Broadside Radiation Characteristics

Chinnathambi Murugan and Thandapani Kavitha

This study presents an aperture-coupled slot-fed antenna specifically designed to operate in two frequency bands. It functions seamlessly within the 5.2-5.3 GHz and 5.9-6.1 GHz ranges, featuring unique characteristics: emitting monopole radiation at lower frequencies and transitioning to a broadside pattern at higher frequencies. The 5.2-5.3 GHz band is primarily used for high-speed Wi-Fi (IEEE 802.11 standards) and small cells in 5G networks, as well as radar systems. The 5.9-6.1 GHz band supports Intelligent Transportation Systems (ITS), vehicle-to-everything (V2X) communication, and C-band satellite uplink services. With a peak gain of 6.025 dBi, this compact antenna measures 25 mm × 25 mm × 1.6 mm (0.492λ × 0.492λ × 0.0315λ, where λ is the wavelength calculated at 5.9 GHz) and is precisely printed on two FR4 substrates, ensuring both performance and practicality. Thorough measurements of the constructed prototype show a remarkable alignment between simulated and measured results, confirming the antenna's reliability and precision. Its distinctiveness lies in its engineered adaptability, perfectly suited for applications requiring diverse patterns within dual-band scenarios. This adaptability allows for flexible signal reception, making it an ideal choice for situations demanding robust performance across multiple frequency ranges. Given its ability to offer varied pattern configurations, this antenna shows significant promise for applications where flexible and reliable signal reception is crucial.

Adaptive Dual-band Antenna for 5G and ITS Applications with Monopole-to-broadside Radiation Characteristics

2024-11-02

PIER Letters

Vol. 123, 55-60, 2025

doi:10.2528/PIERL24091704

download: 106

Advanced Compact High-Power InGaAs HEMT Self-Oscillator Active Integrated Antenna for IoT Applications

Hanaa El Moudden , Tajeddin Elhamadi , Moustapha El Bakkali and Naima Amar Touhami

This work presents a new negative resistance self-oscillator based on an integrated active antenna and InGaAs HEMT technology, specifically designed for Internet of Things (IoT) applications. A key aspect of this design lies in the series integration of the active circuit and the antenna patch. The fabrication and testing were carried out on an FR4 substrate with a thickness of 0.8 mm. The Harmonic Balance numerical method, implemented in the Advanced Design System tool, was used for the optimization and co-simulation of the system. After simulation and measurement, the proposed self-oscillator, with a compact size of 3.4 x 3 cm², produced very significant results. The simulated output power reached 12.87 dBm at a frequency of 3.07 GHz, while the measured output power was 12.85 dBm at 3.04 GHz, with a recorded phase noise of -78 dBc/Hz at 10 MHz. The qualitative and quantitative performance of the proposed self-oscillating antenna makes it particularly suitable for applications such as satellite mobile communications, GPS, telemetry, and telemedicine.

Advanced Compact High-Power InGaAs HEMT Self-Oscillator Active Integrated Antenna for IoT Applications

2024-10-31

PIER Letters

Vol. 123, 47-54, 2025

doi:10.2528/PIERL24082804

download: 105

A Dual-Band High-Isolated MIMO Antenna Based on Compensation Network for 5G Coal Mine Applications

Yanhong Xu , Nanyue Li , Can Cui , Xuhui Fan , Jianqiang Hou and Anyi Wang

A dual-band MIMO antenna with high isolation is designed in this paper for coal mine applications. Each of the two elements in the designed MIMO antenna is composed of a bident-shaped monopole structure which is designed to cover the 5G NR frequency region (2.51-2.67 GHz, 3.4-3.6 GHz) allocated for coal mine scenario. The two elements are symmetrically placed to achieve high isolation at lower frequency region with an element spacing of 0.09λ at the lowest operating frequency. To further reduce the mutual coupling between the two elements, the decoupling network technique is utilized. In particular, a neutralization line is loaded with an adjustable capacitor and two adjustable inductors on the ground. In this way, an isolation of higher than 20 dB is achieved over the two operating frequency bands for the MIMO antenna, i.e., the isolation is increased by more than 11 dB and 10 dB for the lower and higher bands, respectively. Besides, the good performance of the designed MIMO antenna in terms of correlation values and diversity gain makes it a suitable candidate for 5G MIMO applications under coal mine scenarios.

A Dual-band High-isolated MIMO Antenna Based on Compensation Network for 5G Coal Mine Applications

2024-10-25

PIER Letters

Vol. 123, 41-46, 2025

doi:10.2528/PIERL24090303

download: 122

Design of X-Band Vertical Non-Standard Coaxial-Waveguide Converter

Bo Yan , Zibin Weng , Dalei Yuan and Youqian Su

A non-standard rectangular waveguide-to-coaxial converter designed for the X-band (9.3-9.5 GHz) is presented. This converter builds upon traditional coaxial probe coupling and stepped contact feeds by integrating a Chebyshev impedance transformer and stepped impedance matching technique. The proposed improved converter features a coupling probe combined with a stepped contact, enabling a vertical feed configuration from the bottom. This design offers an effective option for optimizing array antenna layouts. Simulation results indicate that within the operational frequency range, the rectangular waveguide-to-coaxial converter achieves |S₁₁| less than -27 dB and |S₂₁| greater than -0.04 dB. Practical measurements for non-standard rectangular waveguides show a VSWR below 1.1 across the working frequency band.

Design of X-band Vertical Non-standard Coaxial-waveguide Converter

2024-10-25

PIER Letters

Vol. 123, 37-39, 2025

doi:10.2528/PIERL24081908

download: 99

Broadside-Incidence Extinction Measurements of Thin Copper Circular Discs and the Extinction Paradox at 35 GHz

Charles W. Bruce and Sharhabeel Alyones

This article presents millimeter wavelength measurements of the mass normalized extinction cross section (extinction efficiency) of thin copper circular discs at broadside incidence. The extinction efficiencies of the discs were measured as a function of diameter and thickness at a fixed frequency of 35 GHz. The measurements cover a wide range of diameters and thicknesses and were compared with the approximate numerical solution of the problem provided by the CWW code. A good agreement between the measurements and CWW code was achieved after applying the extinction paradox for small particles with high index of refraction to the CWW code calculations.

Broadside-incidence Extinction Measurements of Thin Copper Circular Discs and the Extinction Paradox at 35 GHz

2024-10-21

PIER Letters

Vol. 123, 29-35, 2025

doi:10.2528/PIERL24091002

download: 140

Nonlinear Modelling of k -Band GaN Power Amplifier

Zhanglei Song , Xin Cheng , Fayu Wan , Xiaohe Chen , Eugene Sinkevich , Vladimir Mordachev and Blaise Ravelo

An innovative nonlinear (NL) modelling of K-band power amplifier (KPA) designed and fabricated in Gallium Nitride (GaN) technology operating at frequency f0=24 GHz is investigated in this paper. Two KPA prototypes are characterized by single- and double-frequency tests (SFT and DFT). Then, fitting memory NL model from SFT established for input-output power (Pin-Pout) characteristic @ f0 enables to the confirmation of KPA performance. Accordingly, the KPA presents 27.8 dB gain when Pin increases from -5 dBm to 20 dBm, 40.8 dBm saturation output power, and 38.6% saturation power added efficiency (PAE). Moreover, the DFT with f1=23.995 GHz and f2=24.005 GHz enables the assess to the third-order intermodulation distortion (IMD3) which is assessed from 10.4 dBc to 35 dBc. The KPA critical IMD3 is identified with the Pout variation range from 16.35 dBm to 36.35 dBm. The developed NL model is useful in the future for the electromagnetic interference prediction of multi-carried front-end transceiver communication system due to NL distortion signal.

Nonlinear Modelling of K-Band GaN Power Amplifier

2024-10-14

PIER Letters

Vol. 123, 21-27, 2025

doi:10.2528/PIERL24072302

download: 137

Magnetic Resonance Eddy Current Detection for Rebar Corrosion in Concrete

Xiaoming She , Haitao Chen , Zhengxuan Zhang , Jinming Zhang and Leng Liao

Rebar corrosion is a common hidden danger in concrete structures, posing a serious threat to structural safety. Due to its concealed nature, detecting rebar corrosion remains a significant challenge. Recently, a new detecting principle for internal rebar corrosion: Magnetic Resonance Eddy Current Penetration Imaging (MREPI) is proposed. This method significantly enhances the detection depth of eddy currents through resonance amplification. In this work, the theoretical and numerical analysis of MREPI has been done. The results demonstrate the higher sensitivity than the traditional eddy current testing (ECT). Furthermore, we built an MREPI sensor by using nanocrystalline soft magnetic metal as magnetic core to detect the rebar corrosion. Experimental results show that the proposed sensor can effectively test rebar within concrete, with the imaging patterns of corroded rebar being distinguishable.

Magnetic Resonance Eddy Current Detection for Rebar Corrosion in Concrete

2024-10-08

PIER Letters

Vol. 123, 15-20, 2025

doi:10.2528/PIERL24072403

download: 165

Quantitative Microwave Imaging of High-Contrast Targets with the Incidence of Orbital Angular Momentum Wave

Shasha Hou , Kuiwen Xu , Xiaotong Li , Feixiang Luo , Xiling Luo , Sheng Sun , Wen-Jun Li and Lingling Sun

The inherent nonlinearity and ill-posedness of inverse scattering problems (ISPs) make high-quality target reconstruction challenging. To mitigate some of the difficulties and achieve more accurate and stable reconstructions, a super-resolution imaging method by use of the orbital angular momentum (OAM) wave for solving high-contrast targets is proposed. By the interaction of OAM wave and the material of target, the multiple scattering could be enhanced, and more incoherent wave could be activated. Under the frame of the contraction integral equation for inversion (CIE-I) method, the OAM-inspired CIE-I inversion method (OAM-CIE-I) is introduced to achieve super-resolution imaging of high-contrast targets. OAM electromagnetic waves, generated from a two-dimensional uniform circular array (UCA), are used as the incident field into the imaging model. Orbital angular momentum diffraction tomography (OAM-DT) is used to obtain the initial value of the contrast function containing the super-resolution information, which serves as the initial contrast value for the CIE-I model. Despite the initial contrast value differing significantly from the actual target, it contains incoherent wave information, enabling super-resolution imaging through three optimization iterations. In virtue of the inversion solver of the CIE-I, the inversion ability of the OAM-CIE-I is significantly enhanced. In the comparisons from numerical simulation results with CSI, OAM-CSI, CIE, and OAM-CIE methods, the superiority of OAM-CIE-I is demonstrated.

Quantitative Microwave Imaging of High-contrast Targets with the Incidence of Orbital Angular Momentum Wave

2024-10-03

PIER Letters

Vol. 123, 7-13, 2025

doi:10.2528/PIERL24061103

download: 178

The Development of Multibeam Quarter-Cut Radial Line Slot Array (RLSA) Antennas

Teddy Purnamirza , Junisbekov Mukhtar Shardarbekovich , Muhammad Renaldy Yusma , Muhammad I. Ibrahim , Kabanbayev Aibek Batyrbekovich and Depriwana Rahmi

This research aimed to introduce multibeam quarter-cut Radial Line Slot Array (RLSA) antennas for the first time. These antennas are distinct from the multibeam full-circle RLSA due to the use of quarter RLSA, making it suitable for small devices. To achieve beams directed to the backside, an unconventional approach was taken by placing slots on the antenna's background. A technique comprising the deletion of specific slot pairs in the radiating element was introduced to balance the gain and beam shape. Furthermore, thirty-six multibeam quarter RLSA models were designed and simulated. The best model was then fabricated and measured to validate the simulation results. Consequently, the results showed the possibility of designing multibeam antennas with symmetrical beams in terms of gain, direction, and beamwidth, which were 6.23 dBi, 37˚, 145˚, and 34˚, respectively. The gain of 6.23 dBi was 3 dB less than the single-beam antennas, consistent with the theory of beam splitting. Additionally, antennas exhibited low reflection and a broad bandwidth suitable for Wi-Fi needs. Finally, the agreement between measurement and simulation validated the design of antennas.

The Development of Multibeam Quarter-cut Radial Line Slot Array (RLSA) Antennas

2024-09-30

PIER Letters

Vol. 123, 1-6, 2025

doi:10.2528/PIERL24062503

download: 176

Near-Field Shaping with Arbitrary Patterns and Poarization by Conformal Tensor Impedance Modulated Holographic Metasurfaces

Hui-Fen Huang and Zi-Yi Xiang

Arbitrarily shaped near field with arbitrary polarization is practical application requirements. Our previous work proposed combining the phase conjugation (PC) and planar tensor impedance modulated holographic metasurface (TIMHMS) for arbitrarily shaped near field with arbitrary polarization. This paper proposes to generate arbitrarily shaped near field with arbitrary polarization by cylindrical conformal TIMHMS based on PC and Blackman window function. For the first time to the knowledge of the authors, arbitrarily shaped near field with arbitrary polarization is generated by conformal TIMHMSs. As example, two cylindrical conformal TIMHMSs are constructed at 30GHz for rectangle-shaped near field: (LHCP, z = 100 mm) and (LP, z = 200 mm), where LHCP and LP are left hand circular and linear polarizations, respectively. Blackman window function is used to optimize the cylindrical conformal TIMHMS design for optimized field pattern efficiency and low sidelobe. The calculated, simulated, and measured results agree well, and validate the proposed design method for conformal TIMHMS. The designed conformal TIMHMSs have the advantages of high pattern efficiency 42.1%, flexibly shaped field patterns and polarizations, and low sidelobe (-15 dB). The design method does not need complicated calculations and can be used in the upcoming sixth-generation wireless networks with required shaped nearfield for Radio Frequency Identification, holographic imaging, biomedical applications, etc.