Daotong Li

• PhD
• Chongqing University

In this letter, a novel high-efficiency millimeter-wave (mmWave) rectifier based on substrate-integrated suspended lines (SISLs) is proposed for the first time. The rectifier consists of a waveguide-to-SISL transition structure, an impedance matching network, a Schottky barrier diode (SBD), and a dc-pass filter. By utilizing a rectangular waveguide...

In this paper, a novel pattern and beamwidth reconfigurable cylindrical dielectric resonator antenna (CDRA) is proposed. The pattern reconfigurable structure is achieved by a pair of 3D-printed arc-shaped parasitic metal panels, which are capable of high-gain beam scanning with ±24° in the H-plane and ±18° in the E-plane radiation, respectively, wi...

A high gain filtering quasi-Yagi antenna based on compressed third-order mode dipole is presented in this paper. The meander line structure is employed on the dipole to realize the compressed dipole. The current distributions on the meander structure are equal amplitude and out-of-phase to cancel the far-field radiation to realize sidelobes suppres...

In this paper, a dual-band polarization-independent terahertz (THz) metamaterial absorber (MA) based on metal-insulator-metal (MIM) configuration is proposed and measured. The flexible material polyimide is chosen as the substrate. The periodic metal array cell on the top surface is fabricated utilizing four F-shaped metal strips, and due to the hi...

A novel method for estimation and optimizing structural parameters of coupled-line bandpass filters (BPFs) using transformer-based estimator (TBE) and multilayer perceptron (MLP) is proposed. Once trained, the TBE can quickly obtain the predicted values of the BPF structural parameters from desired S-parameters, while the trained MLP can replace th...

In this paper, a compact novel type of wide-stopband bandpass filter (BPF) is presented based on perturbed dual-mode substrate integrated waveguide (SIW) cavity. The perturbed metallic vias are introduced at the center of SIW cavity to achieve a dual-mode SIW cavity by shifting the resonant frequency of TE101 mode toward TE201 mode. Moreover, by se...

A self-packaged air-filled substrate-integrated waveguide (AFSIW) filtering power divider (FPD) operating at Ka-band with the characteristics of low loss, broadband, high in-band isolation, and sharp roll-off skirt is proposed in this letter. The filtering network is dexterously integrated into the branches of the T-junction, which is simple and co...

In this paper, a novel compact filtering power divider (FPD) with sharp frequency selectivity, high in-band isolation and deep out-of-band suppression is proposed. The realization of filtering and power division functions is achieved by utilizing of a U-shaped resonator coupled square ring resonator (UR-CSRR). The UR-CSRR configuration is proposed...

Two broadband dual-polarized band-notched crossed dipole antennas based on the grounded coplanar waveguide (GCPW) filter for 2G/3G/4G/5G base station are proposed in this paper. Two antennas with two and three radiation nulls are displayed to demonstrate the design innovation. Firstly, a wideband crossed dipole antenna with GCPW feed structure is d...

In this paper, two filtering power dividers (FPDs) with wideband and high in-band isolation, sharp bandpass selectivity and deep out-of-band rejections based on parallel coupled lines (PCLs) and anti-parallel coupled lines (APCLs), respectively, are proposed. The open-stub loaded PCL (OSL-PCL) and open-stub loaded APCL (OSL-APCL) are respectively p...

In this brief, two compact tri-band substrate integrated waveguide (SIW) bandpass filters (BPFs) with high selectivity and controllable center frequencies are presented based on the proposed tri-mode SIW resonant cavity perturbed by metallized vias. The resonant characteristics of the tri-mode SIW cavity are first analyzed, and the impacts of some...

In this paper, two compact dual-band substrate integrated suspended line (SISL) filtering antennas with high selectivity based on dual gap-coupled patches are proposed. By using a quasi-I-shaped feedline, etching longitudinal slots on two patches placed symmetrically and connecting a metal strip with both patches through metallized vias, three radi...

This article presents a design strategy of dual-/tri-/quad-band substrate-integrated waveguide (SIW) bandpass filters (BPFs) based on a single perturbed multimode SIW cavity. By loading metallized vias or slotlines perturbed structures at the center of the proposed SIW cavity, the first four independent adjustable resonant modes of TE101, TE201, TE...

Single-layer dual-/tri-band substrate integrated waveguide (SIW) filtenna based on multifunctional cavity-backed slots is proposed in this communication. The cavity-backed slots etched on the SIW cavity can be considered as radiators as well as resonators. When a pair of back-to-back open-loop slots embedded with a straight slot are etched on the S...

A compact planar printed wideband filtering quasi-Yagi antenna without any extra external filtering circuit for vehicular communication is proposed in this paper. It consists of a microstrip-to-slotline transition (MST), a coplanar stripline (CPS), driven elements and parasitic elements which act as directors and filtering elements simultaneously....

A novel filtering nonmagnetic circulator based on the spatiotemporal modulation of microstrip filtering delay network using traditional PCB processing technology is presented in this article. By utilizing switches controlled by periodic signal to realize spatiotemporal modulation of microstrip filtering delay networks with large and flat in-band gr...

A high-gain wideband cylindrical dielectric resonator antenna (CDRA) based on semi-cylindrical grooved structure is presented in this brief. A semi-cylindrical grooved structure is used to combine the higher-order ${\mathrm{ HEM}}_{12\sigma }$ mode of the CDRA with that of the slot resonant mode, so to realize a hybrid radiation mode with high ga...

This paper presents a compact high-efficiency broadband microwave rectifier for free-space Radio Frequency (RF) energy harvesting. Lumped-element components and voltage-doubling circuits are used to improve output efficiency and power, widen frequency bandwidth, and reduce circuit size. The theoretical model and numerical model of the rectifier cir...

A single-layer dual-band shielded half mode substrate integrated waveguide (HMSIW) bandpass filter using single SIW cavity is proposed in this paper. A metallic wall is established along the longitudinal direction of the complete SIW cavity center and two gaps are etched near the metallic wall, two shielded HMSIW cavities are evolved from the singl...

A compact low-profile differential dual-polarized filtenna without an external filter circuit for vehicular communications is proposed in this paper. It has a compact, low-profile, simple, and symmetrical structure, which consists of four identical quarter circular patches with a pair of crossed feeding lines symmetrically and orthogonally embedded...

An active, compact, wideband, receiving filtenna with power adaptation for space-limited wireless platforms is presented. By organically combining a filtering antenna and a Variable Gain Amplifier (VGA), the proposed co-designed active filtenna is achieved. Its power adaptation is empowered by controlling gain of the VGA unit. A demonstrated protot...

A W-band PIN diode single pole double throw (SPDT) switch with low insertion loss (IL) was successfully developed using a hybrid integration circuit (HIC) of microstrip and coplanar waveguide (CPW) in this paper. In order to achieve low loss of the SPDT switch, the beam-lead PIN diode 3D simulation model was accurately established in Ansys High Fre...

This paper presents a mechanical reliability study of 3-dB waveguide hybrid couplers in submillimeter and terahertz bands. To show the necessity of improving the mechanical properties of the coupler’s branch in submillimeter and terahertz bands, a comprehensive study regarding the displacement of hybrid branch variation with varying width-length ra...

A compact low-profile differential filtering microstrip patch antenna with high selectivity and deep rejection using single-layer substrate is proposed. The presented antenna mainly consists of the quasi-H-shaped patch (QHSP) and the meandering quasi-T-shaped resonator (QTSR) which is composed of two open-end meandering arms in opposite direction a...

In this article, a compact bandpass filter (BPF) with dual‐wideband is developed using single loop complementary split‐ring resonators (CSRRs) loaded substrate integrated waveguide (SIW). The dual‐wideband response is achieved by etching the CSRRs with a bandstop characteristics on a high‐pass SIW filter structure. The characteristics of CSRR and d...

A selectivity‐enhancement technique is presented for design of parallel‐coupled stepped‐impedance resonator (SIR) based dual‐band bandpass filter (BPF) in this article. The presented dual‐band BPF consists of two short‐circuited coupled lines (SCCLs) and a couple of parallel‐coupled SIRs. Theoretical analysis and numerical simulations on the propos...

A compact monopole antenna with enhanced selectivity is designed based on circular disk monopole antenna and signal interference technique (SIT). It is composed of a circular disk monopole and a SIT‐based filtering structure consisting of two pairs of short‐circuited edge coupled stubs loaded on the feeding line. When the filtering structure is jus...

In this paper, a miniaturized dual-band bandpass filter (BPF) with good selectivity based on ring-loaded resonator (RLR) and 0° feed structure is proposed. First, the RLR is investigated theoretically and numerically, and a miniaturized Filter I is designed based on the RLR and filter synthesis approach. Secondly, based on the coupling structure of...

An accurate and efficient method for analyzing the coupling ratio of symmetrical four-port branch waveguide coupler is presented. The method is based on the mode-matching method (MMM) and the odd and even mode analysis, considering the interactions between the fundamental and higher order modes in junctions and discontinuities. It is found that the...

In this article, a crossed dipole antenna with compact size (43 × 43 mm2) and high isolation (42 dB) is proposed using a hybrid balun circuit. The hybrid balun consists of a tapered balun and a Marchand balun. The tapered balun transforms the microstrip line into the parallel feeding lines for one pair of dipoles, and the Marchand balun transforms...

A design strategy of a bandpass filter (BPF) with sharp roll‐off and improved stopband performances is presented in this paper. The proposed filter prototype consists of a couple of parallel‐coupled stepped‐impedance resonators (SIRs) and two short‐circuited coupled lines (SCCLs). The theoretical analysis and numerical simulations on the parallel‐c...

This paper firstly proposes a 3D printed, compact, low-profile, ultra-wideband (UWB) antenna with vertically polarized omnidirectional radiation characteristics. The antenna is composed of one triangular feeding structure, one triangular shorted structure, a common capacitive top hat and two parasitic metallic pins. Compared with traditional UWB an...

A compact microstrip bandpass filter (BPF) with sharp roll-off skirt and broad stopband, consisting of the proposed modified 0° feed structure and the shorted stub-loaded tri-section stepped impedance resonator (SSLTSIR), is presented. The first two high-order parasitic resonant frequencies of the conventional 0° feed structure can be suppressed wh...

A new Wilkinson filtering power divider (PD) with high performance has been presented. By employing four pairs of parallel‐coupled lines and a T‐shaped stub to construct the filtering PD, sharp roll‐off skirts and high stopband rejections can be achieved with three transmission poles and six transmission zeros. Theoretical deduction is presented to...

This paper proposes a novel dual-polarized filtering patch antenna without extra circuit. The proposed antenna shows a quasi-elliptic filtering response with four radiation nulls. One radiation null is achieved with a stacked patch, and three more radiation nulls are introduced by the split ring resonators (SRRs) placed inside the antenna aperture....

In this paper, a dual-band dual-polarized crossed dipole antenna with good anti-interference capability is proposed for 2.4/5 GHz WLAN applications. The proposed antenna covers the WLAN 2.4-GHz band (2.4−2.48 GHz) and 5-GHz bands (5.15-5.85 GHz) with isolation > 27 dB for VSWR < 2. Without extra filtering circuit, a band-notch (3.4−3.6 GHz) is achi...

In this paper, a compact dual-polarized ultra-wideband dipole antenna is realized by exciting three resonant modes using double-loop (DL) dipoles with stepped exponential-shaped (ES) arms. Firstly, a single-loop (SL) crossed dipole antenna using the modified direct feeding (MDF) structure with ES arms is designed and analyzed to achieve wide bandwi...

This letter presents our investigation into a 3-dB waveguide hybrid coupler of a novel structure in the submillimeter frequency band. The proposed coupler has only three coupling branches with a circular cutout at the top and the bottom on both sides of the main branch and is of compact size. The simulation shows that the proposed design has eased...

A compact quad-band filter with controllable central frequencies and bandwidths based on the λ/4 SIR, K inverters and multiple signal transmission paths technique is presented. Two synthesis design approaches and procedures for dual-band filter are firstly proposed, and then the investigations on two kinds of λ/4 SIRs, uniform and stepped impedance...

A modified direct feeding (MDF) structure is proposed in this paper to realize a compact (45 × 45 mm2) wideband dual-polarized antenna with high isolation (33 dB) and low cross-polarization (30 dB). Compared with the conventional crossed dipole antennas, two additional pairs of dipoles are employed as coupling baluns as well as radiators. As a cons...

A compact wideband bandpass filter (BPF) with broad stopband using hybrid half‐mode substrate integrated waveguide (HMSIW) resonator and open‐circuit tri‐section SIRs (OTSIRs) is proposed. A BPF with 3 transmission poles (TPs) and 3 transmission zeros is obtained by cascading the HMSIW resonator and OTSIRs using J and K inverters. A demonstrated wi...

This article proposes a low‐profile dual‐linear polarized multilayer parasitic patch array antenna, which is composed of 3‐layer printed substrates and 1 air gap layer inserted between the lower and middle substrate. There is 1 slotted square patch printed on the lower substrate with 2 excited probes acting as feeding element, and 1 and 4 slotted s...

Double dipoles on a single-layer substrate are utilized to construct a triple-mode printed quasi-Yagi antenna for the multi-band and broadband antenna applications. A stub-loaded dipole generating two resonant modes (i.e., lower dual-mode dipole) is allocated on the underside of a simple dipole (i.e., upper single-mode dipole) introducing the third...

To achieve an improved stopband response including expanded stopband width, increased rejection level, and a smooth S11 phase response, a lowpass filter (LPF) is proposed based on the suspended microstrip line with naturally high characteristic impedance and the radial stub with intrinsic transmission zero. The usually unmentioned phase response, a...

On the basis open stub-loaded tri- and quad-mode resonators, two compact microstrip low-pass filters (LPFs) with deep and ultra-wide stopband are presented. Modal characteristics of the tri- and quad-mode resonators are analysed by even-odd-mode method. Multimode resonator can be modelled as multiple LC resonant circuits and the lumped-element equi...

A multichannel radiometer frontend, which can improve the radiometer sensitivity and utilization of the frequency band dramatically, is proposed based on the principle of bandwidth synthetic technology. The multichannel radiometer, called multichannel bandwidth synthetic radiometer (MCBWSR), consists of multiple conventional radiometer channels, an...

We embed varactors as active circuit elements within a metamaterial absorber to implement a tunable metamaterial absorbers at microwave frequencies. The microwave absorption of the designed absorbers can be tuned by changing the reverse bias voltage on the varactor diodes. The design of varactor-loaded metamaterial absorbers has a low-cost compact...

Cloud detection in multi-temporal optical remote sensing images is a significant task. In this paper, we proposed an efficient method to coarsely detect the cloud via Mean Shift Cloud Detection (MSCD) algorithm, which can work automatically without any reference images. Experimental results on Landsat-8 OLI dataset show the effectiveness of the pro...

Based on multi-mode resonator (MMR) and λ/4 resonators, a miniaturized microstrip quint-band bandpass filter (BPF) with mixed electric and magnetic coupling (MEMC) has been presented. The proposed MMR is employed to generate the 1st, 2nd, and 5th passbands, while the 3rd and 4th ones of close band proximity are achieved by using four coupled λ/4 un...

Currently, implementation of active circuit elements within metamaterials is an effective way to make them electrically tunable. We combine varactors with split copper loops in a metamaterial absorber in order to obtain an electrically tunable microwave response. This absorber has a compact planar structure and a simplified back feeding network. Fl...

Based on open stub-loaded dual- and tri-mode resonators, two miniaturized microstrip tri-band bandpass filters with good performance are presented. A pseudo-interdigital structure is introduced to realize size reduction. The 0° feed network is applied to create at least one transmission zero near the passband edge of each passband, resulting in hig...

This paper presents a compact UWB BPF with a notch band using a novel quadruple-mode resonator and spur-lines. The characteristics of quadruple-mode resonator are investigated by using the odd- and even-mode analysis method. In the design, the resonator is excited by using interdigital-coupled-lines. When the spur-lines are introduced, a notch band...

A wideband bandpass filter under multiple resonances of stepped impedance ring resonator is proposed in this letter. The classical even- and odd-mode method is used to analyze the characteristics of the proposed resonator. It is observed that the proposed filter can operate at a wideband. For demonstration, a filter with central frequency at 2 GHz...

A quadruple-mode resonator based on stub-loaded was proposed. The resonator possesses four resonances over the wide frequency band from 3.1-10.6 GHz, which can be employed to implement an ultra-wideband bandpass filter(BPF) to achieve flat response. The quadruple-mode resonator is investigated by using odd-even mode analysis and weak coupling metho...

This paper presents a new design of power divider for dual-band application, in which both short- and open-ended stubs are applied. Closed-form design equations for the proposed power divider are derived. It is observed that the proposed power divider can operate at a large frequency ratio (2.4-5). For verification, the measured, calculated and sim...

A triple-mode microstrip square ring short stub-loaded stepped impedance resonator (SIR) is proposed for the design of bandpass filters (BPFs). The resonator possesses three resonances over the wide frequency band, which can be employed to implement a BPF with flat response. This kind of the filter is able to control spurious response by changing t...

The microwave radiometer is a highly sensitive receiver capable of measuring low levels of microwave radiation. Limited by the interference or the performance of the pre-detection amplifiers, the bandwidth can not be enlarged infinitely to improve the sensitivity for a single channel radiometer. Some multi-channel radiometers are also reported. The...