Xi-Lang Zhou

A Miniaturized Dual-Band Frequency Selective Surface (FSS) With Closed Loop and Its Complementary Pattern

A single-layer substrate frequency selective surface (FSS) made of miniaturized elements is proposed, with two controllable passbands obtained. Each FSS element consists of a loop wire on the top metal layer and its complementary pattern etched at the bottom one, which provides two transmission poles separated by a transmission zero. An equivalent circuit model is given for predicting the characteristics of the designed FSS, and a good agreement between the simulated and measured transmission coefficients is obtained. Furthermore, the cases of oblique wave incidence and cascading FSSs are also measured and examined.

A Substrate-Integrated Evanescent-Mode Waveguide Filter With Nonresonating Node in Low-Temperature Co-Fired Ceramic

A cross-coupled substrate-integrated evanescent-mode waveguide filter is proposed with a quasi-elliptic frequency response. It is realized with a coplanar waveguide as a nonresonating node to provide an equivalent negative coupling coefficient. The filter prototype is developed with folded and ridge substrate-integrated waveguides (SIWs) in low-temperature co-fired ceramic. Since evanescent-mode and cross-coupling techniques are used in the design of filters, about 90% area reduction and more than 60% volume reduction are achieved, in comparison with conventional planar cavity-coupled SIW filters. Their unloaded Q factor is also improved. In particular, the spurious suppression characteristic of the direct-coupled evanescent-mode waveguide filter is kept by the cross-coupled filter with the nonresonating node structure. All these merits are demonstrated numerically, as well as experimentally, with good agreement obtained between the measured and simulated S-parameters.

A New Type of Periodically Loaded Half-Mode Substrate Integrated Waveguide and Its Applications

A new type of half-mode substrate integrated waveguide (SIW) periodically loaded with different lumped elements and structures is proposed in this paper. The propagation constants, Bloch impedances, and voltage distributions of the Floquet TE-modes are all characterized by solving the eigenvalues of the generalized transmission matrix of a single period. Several typical capacitor-loaded, inductor-loaded, corrugated, and electromagnetic-bandgap (EBG)-loaded half-mode SIWs were fabricated to demonstrate their modal dispersion behavior. The measured and simulated S -parameters, group delays, and simulated electric field distributions in these novel structures are presented, with good agreements obtained for all samples. In particular, their unique controllable cutoff frequencies, multiple bandgaps, and separated monomode regions are also illuminated numerically and experimentally. To further show their applications, a tunable phase shifter is developed using a varactor-loaded structure, with its 3-dB bandwidth of 50% and a maximal tunable range of 88°. In addition, a bandpass filter based on EBG-loaded half-mode SIW is also realized and presented with its special characteristics. It demonstrates that the filter has a sharp upper slope side and a good performance of spurious suppression.

An Extended Doublet Substrate Integrated Waveguide (SIW) Bandpass Filter With a Complementary Split Ring Resonator (CSRR)

An ldquoextended doubletrdquo bandpass filter (BPF) is proposed using a substrate integrated waveguide (SIW) cavity with a complementary split ring resonator (CSRR) etched on its top metal plane. Thus, a single-layer BPF with two transmission zeros is realized successfully, with no additional area or layers occupied. The measured and simulated S-parameters of the filter are presented to show its predicted performance, with good agreements obtained between them.

Evanescent-Mode Bandpass Filters Using Folded and Ridge Substrate Integrated Waveguides (SIWs)

A novel evanescent-mode bandpass filter (BPF) is presented using folded and ridge substrate integrated waveguides (FSIWs & RSIWs). Both measured and simulated S-parameters are presented to show the characteristics, with good agreements achieved between them. It is experimentally validated that such a BPF has better performance in spurious suppression and much smaller size than those of conventional SIW cavity-coupled counterparts.

Bandpass Filter Using Substrate Integrated Waveguide Cavity Loaded With Dielectric Rod

A novel bandpass filter (BPF) is designed using the substrate integrated waveguide cavity loaded with a dielectric rod. The resonant frequencies and unloaded Q-factor are determined by a set of analytical equations. Using the technique of dielectric loading, the proposed BPF has the advantages of compactness, good spurious suppression characteristics, low insertion loss, and low cost, which is demonstrated by good agreement between the simulated and measured S-parameters.

An Adaptive Marching-on-in-Order Method With FFT-Based Blocking Scheme

An adaptive marching-on-in-order (MOO) method with FFT-based blocking scheme is proposed to solve the time-domain electric field integral equation (TD-EFIE) for conductive objects, with the temporal basis of Laguerre polynomials (LP) employed. In contrast to most MOO approaches that utilize a priori fixed order of weighted LP for the temporal variation, we choose suitable polynomial order by computing the relative error of the weighted LP expansions. Thus, the accuracy of the MOO scheme is guaranteed. A general principle for choosing the optimal scaling factor of LP is presented, which is crucial for efficiently predicting scattering information of objects. The fast Fourier transform (FFT)-based blocking scheme is also implemented to reduce the computational complexity to O(NS2 No log2 (No))Numerical results that demonstrate the accuracy and efficiency of this methodology are presented.

Analysis and Application of Novel Structures Based on Split Ring Resonators and Coupled Lines

In this paper, novel structures using split ring resonators (SRRs) and coupled lines are proposed and analyzed. SRRs are etched on three different planes and their propagation characteristics are compared. Two compact narrow band band-pass filters based on these structures are designed and their performances are demonstrated by simulated and measured results, which are in good agreement.

A Novel Multilayer Partial H-Plane Filter Implemented With Folded Substrate Integrated Waveguide (FSIW)

A novel multilayer partial H-plane filter is proposed using folded substrate integrated waveguide (FSIW) and fabricated based on a standard LTCC technology. Evanescent SIW sections are utilized to form coupling structures, and no additional via-holes are introduced except those composing the filter boundaries, with its tolerance sensitivity reduced. The measured and simulated S-parameters of the filter samples are presented to show their superior performance, and good agreements are achieved between them.

A Three-Way Reconfigurable Power Divider/Combiner

In this paper, a three-way reconfigurable power divider/combiner is proposed based on novel switch element with matching network (SEMN) and reconfigurable impedance transformer network (RITN). A good matching performance and a high isolation of the SEMN with one p-i-n diode can be obtained by the parasitic inductance and reverse capacitance of the p-i-n diode involved in matching circuits. With different parameters of one p-i-n diode under forward bias and reverse bias, the reconfigurable impedance matching can be obtained by the RITN with a simple structure. By using four RITNs and nine SEMNs, the three-way reconfigurable power divider/combiner can provide seven different states in the three-path mode, the two-path mode, and the single-path mode. For verification, a 5-GHz three-way reconfigurable power divider/combiner is designed and fabricated. In the three-path mode, measured insertion losses from port 1 to transmission ports (port 2, port 3, and port 4) are less than 0.74 dB and the isolations between transmission ports are higher than 32.1 dB. In the two-path mode with three states, the measured insertion losses are less than 0.93 dB; the isolations between transmission ports, transmission ports and isolation ports, and port 1 and isolation ports are higher than 27.5, 35.1, and 30.5 dB, respectively. In the single-path mode with three states, the measured insertion losses are less than 1.13 dB; the measured isolations between transmission ports and isolation ports are higher than 28.8 dB, and the isolations between port 1 and isolation ports are higher than 28.2 dB at the design frequency.