A Ka‐band power divider/combiner using two side‐inserted magnetic coupling semicircular ring probes

A Ka‐band power divider/combiner with dual magnetic coupling semicircular ring probes is proposed in this paper. Firstly, a broadband microstrip‐to‐waveguide transition with semicircular ring probe is designed based on the side‐inserted structure of magnetic field excitation in a rectangular waveguide. The insertion loss of the proposed transition is less than 0.7 dB in Ka‐band assisted by the dual symmetrical broadband probes and rectangular waveguide. Then, the divider/combiner is proposed using the new transition with magnetic coupling from narrow wall into the rectangular waveguide. The bandwidth of the divider/combiner is more than 9 GHz (from 27 to 36.7 GHz), and the insertion loss of the single divider/combiner is less than 3.3 dB. Finally, the performance of the proposed divider/combiner is validated through simulations and measurements. The proposed design has potential applications in microstrip circuits.     

Miniaturized substrate integrated waveguide filter using fractal open complementary split‐ring resonators

A miniaturized substrate integrated waveguide (SIW) bandpass filter using fractal open complementary split‐ring resonators (FOCSRRs) unit‐cell is proposed. The proposed structure is realized by etching the proposed FOCSRR unit‐cells on the top metal surface of the SIW structure. The working principle of the proposed filter is based on the evanescent‐mode propagation. The proposed FOCSRRs behave as an electric dipoles in condition of the appropriate stimulation, which are able to generate a forward‐wave passband region below the cutoff frequency of the waveguide structure. Since, the electrical size of the proposed FOCSRRs unit‐cell is larger than the conventional OCSRRs unit‐cell; therefore, the FOCSRR unit‐cell is a good candidate to miniaturize the SIW structure. The proposed filter represents high selectivity and compact size because of the utilization of the sub‐wavelength resonators. The introduced filter is simulated by a 3D electromagnetic simulator. In order to validate the ability of the proposed topology in size reduction, 1‐ and 2‐stage of the proposed filters have been fabricated based on the standard printed circuit board process. The measured S‐parameters of the fabricated filters are in a good agreement with the simulated ones. The proposed SIW filters have many advantages in term of compact size, low insertion loss, high return loss, easy fabrication and integration with other circuits. It is the first time that the FOCSRR unit‐cells were combined with the SIW structure for miniaturization of this structure. Furthermore, a wide upper‐stopband with the attenuation >20 dB in the range of 3–8 GHz is achieved. The results show that, a miniaturization factor about 75.5% has been obtained.     

An inline pseudoelliptic self‐packaging substrate integrated suspended line filter with mixed electric and magnetic coupling

A novel compact and self‐packaging inline pseudoelliptic filter is proposed. The proposed filter exploits controllable mixed electric and magnetic coupling using substrate integrated suspended line (SISL) technology. Based on a synchronously tuned coupled resonator circuit with parallel LC resonant tank and admittance inverters, general formulas for extracting electric and magnetic coupling coefficients are derived. Meanwhile, a basic mixed coupled SISL resonator pair is investigated and a systematic design procedure of a second‐order mixed coupled SISL filter is also given. Two prototypes of the second‐order filter with one transmission zero (TZ) at either upper or lower stopband are designed, which is corresponding to either magnetic or electric coupling dominant case. Furthermore, for asynchronously tuned coupled resonator cases, an inline third‐order pseudoelliptic SISL filter characterized by symmetric TZs is designed, fabricated, and measured for validation. The simulated and measured results show a good agreement with the synthesized ones.     

EBG structure with T‐shaped slits for suppression of simultaneous switching noise

In this article, electromagnetic band gap (EBG) structure with T‐shaped slits is proposed for suppressing simultaneous switching noise. T‐shaped slits, bridges, and the solid ground plane are used to constitute the novel L‐EBG structure. Considering a threshold of ?35 dB, the stopband of the proposed EBG structure is about 7.29 GHz which is 1.68 GHz wider than that of a conventional L‐EBG structure. Measurement results confirm the wide bandwidth of the prototype that is predicted in simulations. In addition, the lower and upper cutoff frequencies are estimated by use of lumped‐component circuit models and parallel‐plate waveguide models, respectively. Moreover, the IR‐drop and dc resistance are examined through simulations. Additionally, common signal integrity issues in a power distribution network such as IR‐drop, DC resistance, and eye diagrams are investigated and compared to a conventional L‐EBG structure. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:419–426, 2015.     

Effect of guard‐ring on the DC and high‐frequency performance of deep‐submicrometer metal oxide semiconductor field effect transistor

The influence of guard‐ring (GR) on the direct current (DC) and high‐frequency performance of deep‐submicrometer metal oxide semiconductor field effect transistors (MOSFETs) is investigated in this study. MOSFETs with four different GRs are fabricated using 90 nm complementary metal oxide semiconductor (CMOS) process, and a detailed comparative study on their device performances is performed. A united DC and small signal equivalent circuit model that takes into the effect of GR is developed. A set of simple, but efficient formulas provide a bidirectional bridge for the S parameters transformation between devices with different GRs. The corresponding model parameters for MOSFETs with different GRs are determined from S parameter on‐wafer measurement up to 40 GHz. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:259–267, 2014.     

Novel compact planar electromagnetic band‐gap structure using for ultra‐wideband simultaneous switching noise suppression

In this article, by analyzing the equivalent circuit mode for electromagnetic bandgap (EBG), a novel compact planar EBG structure is proposed for overcoming the drawback of narrow bandwidth of conventional EBG structures. The novel design is based on using meander lines to increase the effective inductance of EBG patches. The simulated and measured results demonstrate the simultaneous switching noise (SSN) can be mitigated with an ultra‐wideband from 280 MHz to 20 GHz at the restraining depth of ?40 dB. Compared with the traditional L‐bridge and meander lines EBG structures, this novel structure has the advantages of suppression bandwidth and fabrication cost. Moreover, signal integrity is achieved by the time‐domain simulation. The proposed structure provides a new kind of theoretical designing reference for EBG structure to improve the bandwidth of restraining SSN. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:429–436, 2014.     

Beam scanning annular slot‐ring antenna array with via‐fence for wireless power transfer

Wireless power transfer has been the field of research for many decades, and with technological advancement and increase in wireless mobile devices, the future of wireless power transfer technology is very promising. The major requirement of wireless power transfer is an efficient and compact antenna array with high gain and flawless scanning performance. In this article, a 4 × 8 element array is proposed with a gain of 18 dB and scanning capability of ±45^° in azimuth and elevation plane at 5.8 GHz. The overall size of the array is 100 mm × 200 mm. The element separation in the array is only 0.48 λ. There was strong mutual coupling due to smaller separation, which has been minimized with the application of via‐fence around the antenna element. A dual feed circularly polarized annular slot‐ring antenna is proposed and analyzed with via‐fence to develop an array of 4 × 8 elements. The antenna array reflection coefficient obtained is less than 20 dB for different scan angles and the gain of the array obtained is also within 2 dB for ±45^° scan angles.     

A new type of the air‐filled substrate integrated gap waveguide resonator

This article presents the design and analysis of an air‐filled substrate integrated gap waveguide (ASIGW) resonator. The electromagnetic field of each resonant mode in the resonator is studied by theoretical modeling and EM simulation. Besides, the relationship between the dimensions and Q_u is analyzed and the Q_u of the resonator can be as high as 2080 at Ku band. Compared with conventional rectangular waveguide resonator and gap waveguide (GW) resonator, the proposed ASIGW resonator can be fabricated more easily. Compared with the substrate integrated waveguide resonator, the ASIGW resonator is more tolerant with dimensional errors and with less degenerate modes. As an example, a fifth‐order band‐pass filter based on the ASIGW resonators is presented to verify the previous conclusions.     

Design of a compact orthogonal fed self‐diplexing bowtie‐ring slot antenna based on substrate integrated waveguide

In this article, a novel design of compact cavity‐backed slot antenna based on substrate integrated waveguide (SIW) technology is presented for dual‐frequency communication services. A single layer printed circuit board is applied to implement the proposed antenna. The bowtie‐ring slot engraved on the SIW square cavity is excited using two orthogonal microstrip feed lines to operate at two distinct frequencies (6.62 GHz and 11.18 GHz). The proposed antenna allows each of these frequencies to be designed independently. A prototype of the proposed cavity‐backed antenna that radiates at both 6.62 GHz and 11.18 GHz is fabricated and measured. The port isolation better than 29.3 dB is achieved by utilizing the transmission zeros (TZs), which are produced due to the orthogonal feed lines, TE₁₁₀ mode and coupling between the TE₁₂₀ and TE₂₁₀ modes. The measured peak gains of the proposed diplexing antenna are 5.77 dBi and 5.81 dBi at lower and upper resonating frequencies, respectively. The proposed dual‐frequency antenna exhibits the front‐to‐back‐ratio (FTBR) and cross‐polarization level greater than 26 dB and 21 dB, respectively, at both resonating frequencies.     

Design and optimization of cross‐coupled substrate integrated waveguide filters using space mapping method

This work presents an efficient method for the design of substrate integrated waveguide (SIW) filters. The proposed design approach is based on a combined use of equivalent circuit model of a filter and a space mapping technique. A reduced number of full‐wave evaluations are needed, leading to a reduced optimization time. A novel SIW filter with improved stop‐band characteristic using cross‐coupling has been proposed. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:360–366, 2014.     

Concurrent adaptive beamforming for standard hexagonal array based on dual norm‐constraint correntropy in the presence of alpha stable noise

This article presents dual norm‐constraint correntropy beamforming methods for standard hexagonal array (SHA) to mitigate the effects of alpha stable noise and maintain the sparsity of filter coefficients. Both goals are achieved simultaneously through the use of norm regularization constraint and the novel convex combination technique. Firstly, we construct constrained optimization equations considered the constraints present in the constrained least‐mean‐square (CLMS) algorithm by incorporating the maximum correntropy criterion (MCC). In addition, in order to decrease the number of active elements for limited power supply array system, we introduce an L1‐norm equation to the list of constraints of the adaptive filter that forces the coefficients with small magnitudes to zero. Then, we utilize the convexity and stability of L2‐norm to devise the constrained maximum correntropy gradient L2‐norm (CMCG‐L2) for further reducing the misadjustment caused by alpha noise and improving the directivity performance of the adaptive beamformer. A novel convex combination scheme is also reported to satisfy the conflicting requirements between the sparsity and mean‐square‐error. Our simulation results demonstrate the superiority of the proposed methods over other previously developed beamforming techniques.     

Spurious‐response suppression of substrate integrated waveguide filters using multishape resonators and slotted plane structures

This article introduces effective techniques to improve the stopband frequency response of substrate integrated waveguide filters. First, a filter is constructed by using different cavity resonators which resonate at the same fundamental mode but at different high‐order modes. A cascade connection of circular and rectangular cavities is used to separate high‐order modes, because the second resonant mode of the circular cavities is more than rectangular ones. Second, inserting transverse radiating slots at the proper positions of cavities, their second longitudinal resonant modes are shifted down and effectively rejected. Third, four cells of slotted plane structure (SPS) are adopted to the top plane of the both input and output feed lines of the filter to reject the undesired passbands or improve steepness of the filter. Also, a combination of the radiation slots with SPS is used to reject the spurious responses accompanied by sharp steepness of the filter. Comparing between the measurement values and simulation results verifies the effectiveness of the proposed configurations and the hybrid technique. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

A piezoelectric transducer‐tuned microstrip‐ring resonator oscillator operating at the second resonant mode of the ring resonator

A microstrip open‐loop resonator oscillator operating at even modes is proposed. The even mode of the ring circuit can be predicted by using a simple transmission‐line model. The new oscillator has a characteristic similar to that of a push‐push oscillator. In addition, in comparison with the push‐push oscillator, the new oscillator with one active device can minimize the size and lower the cost. A voltage‐controlled piezoelectric transducer (PET) is used to vary the resonant frequencies of the ring resonator, which in turn tunes the oscillator with a good tuning range of 4.9% at around 12.1 GHz. This tuned oscillator should have many applications in wireless systems. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

FPC‐free LCD panel with capacitive coupling for transmission of signals and power

Abstract— A flexible‐printed‐cable (FPC) free liquid‐crystal‐display (LCD) panel by using a capacitive‐coupling technique has been developed. A QQVGAeight‐color image was successfully displayed for the first time without attaching any signal or power cables to the panel. The receiving circuitry and capacitive‐coupling electrodes were integrated on the LCD panel using a low‐temperature polysilicon (LTPS) fabrication process. In the proposed digital coding method, the receiving circuit converts derivative waveform signals via the capacitive coupling to conventional logic‐level signals. The maximum data rate of 2.4‐Mbps × 3ch (RGB) was achieved. In addition, LTPS low‐capacitance diode bridge and regulator enabled us to obtain stable DC power of 2.4 mW on the panel from the AC‐power signal. This study is the first step towards integrating the wireless‐communication function on the display panel to achieve a high‐value‐added flat‐panel display (FPD).     

Analysis and design of a fully integrated CMOS low‐noise amplifier for concurrent dual‐band receivers

This article thoroughly analyzes a concurrent dual‐band low‐noise amplifier (LNA) and carefully examines the effects of both active and passive elements on the performance of the dual‐band LNA. As an example of the analysis, a fully integrated dual‐band LNA is designed in a standard 0.18‐μm 6M1P CMOS technology from the system viewpoint for the first time to provide a higher gain at the high band in order to compensate the high‐band signal's extra loss over the air transmission. The LNA drains 6.21 mA of current from a 1.5‐V supply voltage and achieves voltage gains of 14 and 22 dB, input S₁₁ of 15 and 18 dB, and noise figures of 2.45 and 2.51 dB at 2.4 and 5.2 GHz, respectively. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Novel analysis of the size and orientation dependent resonance phenomenon of the microstrip line coupled complementary split‐ring resonator

The purpose of this article is to provide a comprehensive investigation on the resonance phenomenon of microstrip line coupled complementary split‐ring resonator (CSRR) with different orientation and relative size. It is shown that when the relative size of the CSRR is smaller than the host line, the CSRR with its slit oriented orthogonal to the line axis will not excite effectively and show weak resonance behavior. However, when the slit is positioned along the line axis, the cross‐polarization effect comes into play, which excites the CSRR through the mixed coupling. To ensure the correctness, several numerical simulations are carried out for different substrate height and relative permittivity. Finally, a prototype is fabricated and measured for the experimental validation.     

Support‐vector modeling of electromechanical coupling for microwave filter tuning

This article presents a support‐vector modeling method for electromechanical coupling of microwave filter tuning in the case of the scarcity of experimental data available. This has been done for the purpose of establishing an accurate coupling model which can be used in an automatic tuning device of volume‐producing filters. In the method, a coupling model that reveals the effect of mechanical structure on the filter electrical performance is established by using a proposed algorithm which can incorporate multi‐kernel and prior knowledge into linear programming support vector regression (LPSVR). Some experiments from three microwave filters have been performed, and the results confirm the effectiveness of the support‐vector modeling method. Moreover, the comparative results also show that the proposed multi‐kernel prior knowledge LPSVR can improve the data‐driven modeling accuracy of small dataset. The proposed algorithm show great potential in some problems where a sufficient experimental data is difficult and costly to obtain, but some prior knowledge data from a simulation model can be easily obtained. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Novel ultra‐compact two‐dimensional waveguide‐based metasurface for electromagnetic coupling reduction of microstrip antenna array

A novel ultracompact two‐dimensional (2D) waveguide‐based metasurface is proposed herein and applied for the first time to reduce mutual coupling in antenna array for multiple‐input multiple‐output applications. The unit cell of the proposed 2D waveguide‐based metasurface is ultracompact (8.6 mm × 4.8 mm, equal to λ₀/14.2 × λ₀/25.5) mainly due to the symmetrical spiral lines etched on the ground. The metasurface exhibits a bandgap with two transmission zeros attributing to the negative permeability in the vicinity of magnetic resonance and the negative permittivity in the vicinity of electric resonance. Taking advantage of these two features, a microstrip antenna array is then designed, fabricated, and measured by embedding an 8 × 1 array of the well‐engineered 2D waveguide‐based metasurface elements between two closely spaced (9.2 mm, equal to λ₀/13.3) H‐plane coupled rectangular patches. There is good agreement between the simulated and measured results, indicating that the metasurface effectively reduces antenna mutual coupling by more than 11.18 dB and improves forward gain. The proposed compact structure has one of the highest reported decoupling efficiencies among similar periodic structures with comparable dimensions. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:789–794, 2015.     

High efficient method for calculating S‐parameters of microwave filter from coupling matrix

In this article, a high‐efficient approach is presented for obtaining S‐parameters from coupling matrix of a microwave filter whether it is lossless or lossy (assuming all the resonators with the same unloaded Q). Computing time is usually large because inversion matrix needs to be carried out once at each frequency in traditional method. By making the application of matrix inversion Lemma and eigenvalue decomposition theory, the matrix inversion operation is replaced by one‐time matrix eigenvalue decomposition in the whole process, no matter how many frequency we need to concern. After reorganizing the equations of the S‐parameters, the time complexity is decreased from O( N ³ ) to O( N ). An example of 14th cavity cross‐coupled filter is reported for illustrating the capabilities of the new proposed approach. Compared with the general method, the time spending on computing was shortened by 70% with our new approach. Therefore, the proposed approach will be very popular and suitable in the industry.     

Robust Kalman filtering for nonlinear multivariable stochastic systems in the presence of non‐Gaussian noise

The presence of outliers can considerably degrade the performance of linear recursive algorithms based on the assumptions that measurements have a Gaussian distribution. Namely, in measurements there are rare, inconsistent observations with the largest part of population of observations (outliers). Therefore, synthesis of robust algorithms is of primary interest. The Masreliez–Martin filter is used as a natural frame for realization of the state estimation algorithm of linear systems. Improvement of performances and practical values of the Masreliez‐Martin filter as well as the tendency to expand its application to nonlinear systems represent motives to design the modified extended Masreliez–Martin filter. The behaviour of the new approach to nonlinear filtering, in the case when measurements have non‐Gaussian distributions, is illustrated by intensive simulations. Copyright © 2015 John Wiley & Sons, Ltd.