Half-mode Substrate Integrated Waveguide Structure Research Articles

Super-compact equal/unequal half-mode substrate integrated waveguide filtering power dividers using complementary G-shaped resonator

ABSTRACT In this paper, three super-compact equal/unequal filtering power dividers (FPDs) by combining the half-mode substrate integrated waveguide (HMSIW) platform and the metamaterial unit cell are proposed. To miniaturized the total dimension of the proposed equal/unequal FPDs, the evanescent mode technique, the half-mode technique, and the stepped-impedance resonator (SIR) technique have been utilized, simultaneously. In the modified metamaterial unit cell, which is called the complementary G-shaped resonator (CGR) unit cell, the quasi stepped-impedance slot line is replaced instead of the conventional slot line in the circular complementary split-ring resonator (CSRR) unit cell. Accordingly, the electrical size of the modified CGR unit cell is smaller than the conventional circular CSRR unit cell with the same physical sizes. Employing the introduced CGR unit cell and HMSIW structure, three equal/unequal FPDs with arbitrary power-dividing ratios have been designed and simulated. To illustration the performance of the proposed components, three HMSIW FPDs with different power division ratios of 1:1, 1:4, and 1:8 have been fabricated and measured. A reasonable agreement between simulated and measured results has been achieved. The results demonstrate that a miniaturization factor of about 0.64 is achieved.

Polarization-Flexible and Frequency-Scanning Leaky-Wave HMSIW Antenna for Vehicular Applications

To achieve multifunctional communication and safe driving of a vehicle, a half-mode substrate-integrated waveguide (HMSIW) leaky-wave frequency-scanning antenna with flexible polarization is proposed in this article. It includes two linearly polarized interdigital slot antennas, a compact directional coupler, and microstrip transition lines. It can generate either linear polarization (LP) for base station communication or circular polarization (CP) for satellite navigation by configuring the means of excitation. Its radiation beam can be continuously steered with varying frequency in either the LP or the CP state, which is of benefit to safe vehicular driving. In addition, the use of the HMSIW structure reduces the size of the antenna by almost one-half in comparison with the full SIW structure. Measurements were performed on antenna scattering parameters, radiation patterns, gain, and axial ratio (for CP states); the results show good agreement with the simulated results. With its low profile, low weight, low cost, and capability for continuous frequency scanning and variable polarization states, the multifunctional antenna could be extensively used for adapting to changes in environmental conditions or system requirements.

Frequency generator demonstration using half mode Substrate Integrated Waveguide (SIW) structures for chipless Radio Frequency Identification (RFID) reader

A frequency generator based on the forward coupler principle is proposed. The proposed design, intended for high-frequency applications, uses Half-Mode Substrate Integrated Waveguide structure to realise the forward coupler. It thus achieves compactness, requiring approximately half the area compared to Substrate Integrated Waveguide structures, and supports non Transverse Electromagnetic (TEM) functionality. The non-TEM environment provides the flexibility to use the frequency generator for chipless Radio Frequency Identification readers in the sub-GHz band and mm-wave range. Full-wave simulations and the subsequent measurements on a prototype developed on Rogers 3006 substrate performed for the forward coupler resonators and frequency generator validate the proposed design concept.

Half-mode substrate integrated plasmonic waveguide for filter and diplexer designs

A half-mode substrate integrated waveguide (HMSIW) combined with spoof surface plasmon polariton (SSPP) structure is proposed to realize bandpass filter (BPF) characteristic and miniaturization, which is termed as the half-mode substrate integrated plasmonic waveguide (HMSIPW). Compared with the conventional HMSIW structure having identical cutoff frequency, this new design of HMSIPW not only supports SSPP modes, but also realizes a transversal size reduction of 19.4% and longitudinal reduction of more than 60%. Then, a diplexer based on two back-to-back placed HMSIPW BPFs is designed, and it has only one row of metallized via holes to further reduce the transversal size. The experimental prototypes of the filters and diplexer have been manufactured, and the measurement results agree well with simulation ones. Due to the size miniaturization and simple structure, the proposed designs will have many potentials in the integrated devices and circuits for wireless communication systems.

Ultra-Compact Dual-Band Half-Mode substrate integrated waveguide filter and filtering power divider based on metamaterial concept

In this paper, a novel dual-band (DB) half-mode substrate integrated waveguide (HMSIW) filter and three novel equal/unequal DB HMSIW filtering power dividers (FPDs) based on the metamaterial concept with ultra-compact dimensions are proposed. The working principle of the proposed configurations is based on the theory of evanescent-mode propagation. Based on the metamaterial concept, a novel compact metamaterial unit cell with double negative permittivities by combining two different types of metamaterial unit cells has been introduced. By loading the proposed metamaterial unit cell with dual negative effective permittivities at different frequencies on the HMSIW surface, two forward passbands have been generated, independently. These two passbands are located below the waveguide cut-off frequency of the dominant mode in the HMSIW structure, which have been designed for WiMAX and WLAN applications. The resonance frequencies of each metamaterial unit cells can be arbitrarily regulated. Accordingly, by resizing the dimensions of each unit cells, the center frequencies of the introduced unit cell could be separately controlled. Four different techniques have been utilized to reduce the size of the proposed devices, which are the evanescent mode technique, HMSIW technique, meander technique, and fractal technique. To illustrate the performance of the proposed structures, the designed dual-band filters (DBFs), and equal DB FPD have been fabricated and measured. A reasonable agreement between simulated and measured results has been achieved. The total size of the proposed HMSIW DBF and FPD is about 0.10 λg × 0.10 λg. The proposed devices have many advantages in terms of compact size, low insertion loss, high selectivity, easy integration with the other planar circuits, and flexible bandwidth allocations.

HMSIW- and QMSIW-based antenna for wireless communication application

PurposeThe purpose of this paper is to design and develop half-mode substrate-integrated waveguide (HMSIW)- and quarter-mode substrate-integrated waveguide (QMSIW)-based antennas for wireless communication application. The developed antennas offer advantages in terms of compactness, high gain and better isolation between the ports.Design/methodology/approachInitially, the tri-band substrate-integrated waveguide-based antenna is designed using a slot on the ground plane. Then, the same structure has been bisected into two parts for the development of the HMSIW structure. Again the concept of the slot is used for the realization of a dual-band antenna. QMSIW-based structure is designed with further dividing HMSIW structure into two parts. Simulation has been carried out with the use of a high-frequency structure simulator (HFSS) software, which used a finite element-based solver for the full-wave analysis.FindingsThe proposed HMSIW-based dual-band antenna resonates at two different frequencies, namely, 5.81 GHz with 4.5 dBi gain and at 6.19 GHz with 6.8 dBi gain. Isolation between two ports is 20 dB. The overall dimensions of the proposed model are 0.39 λ × 0.39 λ. Similarly, QMSIW-based antenna is resonated at 5.66 GHz of the frequency with the 3 dBi gain. Frequency tuning is also carried out with the change in the slot dimension to use the proposed antenna in various C (4–8 GHz) band applications.Originality/valueThe proposed antennas can use C band wireless frequency application. The proposed structure provides better performance in terms of isolation between the ports, small size, high front-to-back ratio and higher gain. It is fabricated for the proof of concept with the RT Duroid 5880 substrate material having a 2.2 permittivity. Measured results show a similar kind of performance as a simulated one.

Bandwidth Enhancement on Half-Mode Substrate Integrated Waveguide Antenna Using Cavity-Backed Triangular Slot

This paper proposes bandwidth enhancement of a cavity-backed slot antenna using a triangular slot on a half-mode substrate integrated waveguide structure antenna. The bandwidth enhancement was achieved by combining the fixed TE101 and the downward shifting TE102 modes, resulting in hybrid modes. The design evolution of the slot antenna from a half nonresonating rectangular slot to a triangular slot antenna increased the fractional bandwidth. The simulation result showed that fractional bandwidth increased from 6.27% to 9.1%. It was confirmed by measurement that the fractional bandwidth of 9.87% was achieved which reflects a 350 MHz bandwidth with center frequency at 3.84 GHz. The measured gain at center frequency was 4.2 dBi. It is shown that the radiation characteristics obtained from both measurement and simulation results are in very good agreement.

Half mode rogers RT duroid 5880 substrate integrated waveguide cavity backed V-slot antenna for C-band applications

A double band substrate integrated waveguide (SIW) and half-mode substrate integrated waveguide (HMSIW) with cavity backed planar slot antenna is proposed in this research work. The introduced antenna receives an aggregate of two SIW cavities of various dimensions through coupling window. The arrangement of V-shaped slots produces various hybrid modes, which can be adjusted by changing the size of the slot. The advantage of using V-shaped slots over U-shaped slots is improved return loss without affecting the central frequency. Two SIW cavities stacked with V-shaped slots are utilized to energize four firmly arranged hybrid modes in C band (4–8 GHz) to acknowledge double band reaction. The minimal HMSIW structure antenna even demonstrates a superior performance while decreasing almost half size of the SIW antenna.

Millimeter-Wave On-Chip Bandpass Filter Based on Spoof Surface Plasmon Polaritons

A gallium arsenide (GaAs)-based millimeter-wave broadband bandpass filter (BPF) is proposed based on slotted half-mode substrate integrated waveguide (HMSIW) spoof surface plasmon polaritons (SSPPs). The center frequency and bandwidth of this SSPP-based on-chip BPF can be easily controlled by tuning the geometry dimensions of the SSPP unit cell, which is attributed to its unique dispersion characteristics. For demonstration, a prototype of the proposed BPF is fabricated and experimentally characterized, with good agreement between the simulated and measured results. Due to the ability of the strong electric field confinement, the proposed on-chip SSPP structure has lower coupling feature with closely-spaced transmission line circuits than its counterpart traditional HMSIW structure.

Miniaturized half-mode substrate integrated waveguide diplexer based on SIR–CSRR unit-cell

A miniaturized diplexer based on half-mode substrate integrated waveguide (HMSIW) technology by loading a novel metamaterial unit-cell is proposed. The stepped-impedance resonator (SIR) technique has been used in order to miniaturize the physical size of the conventional complementary split ring resonators (CSRRs). The proposed metamaterial unit-cell, which is called SIR–CSRR, consists of two modified rings which the stepped-impedance slot lines are utilized instead of the conventional slot lines in the CSRRs. The proposed diplexer has been designed by cascading two bandpass filters with different center frequencies. The HMSIW bandpass filters are implemented by etching two SIR–CSRR unit-cells with different sizes. The design procedure is based on the theory of evanescent mode propagation which the SIR–CSRR unit-cells behave as an electric dipoles. A forward-wave passband below the intrinsic cutoff frequency of the HMSIW structure has been achieved by loading the SIR–CSRR unit-cells on the metal surface of the HMSIW structure. This proposed diplexer represent high selectivity and compact size by using of the sub-wavelength resonators. The designed diplexer has been fabricated and experimental verification have been provided. The measured results are in a good agreement with the simulated ones. The total size of the proposed diplexer is about 0.27λg × 0.11λg. The proposed diplexer show significant advantages in terms of size reduction, low loss, high selectivity, high Q-factor, easy bandpass frequency shifting, easy fabrication and, easy integration with other planar microwave circuits.

Half‐mode substrate‐integrated waveguide based band‐pass filter for C band application

AbstractDesign and development of half mode substrate integrated waveguide (HMSIW) for a C band application is proposed here. First SIW structure is designed and developed for the cut‐off frequency 5 GHz, and then HMSIW structure is designed and developed from the same structure. Simulated and measured results of both the structures are compared for the verification. A band pass filter (BPF) is designed using HMSIW structure based on transverse slots. Tuning of frequency is carried out by changing the slot length. All the simulation is carried out with the use of high frequency structure simulator (HFSS). BPF provides the pass band from the frequency range of 7.1 to 7.2 GHz with insertion loss less than 2 dB and return loss more than 22 dB. HMSIW structure is further optimized by inserting parallel RLC resonator in between two transverse slots. Measured results are similar with the simulated one.

Compact Multilayer Half Mode Substrate Integrated Waveguide 3-dB Coupler

In this letter, a wideband compact 3-dB coupler is designed based on the multilayer half mode substrate integrated waveguide (HMSIW) theory and Bethe hole coupling theory. The design utilizes higher band of quasi-TE0.5,0 mode in HMSIW and dual-layer structure to reduce the size of component. This letter also theoretically proposes a relationship between SIW and HMSIW broad wall coupler with the same coupling section, which can obviously simplify the design procedure and maintain stable coupling differences. Meanwhile, this coupler shows a 3-dB coupling over a wide bandwidth with a single row of only five small apertures, which needs more in SIW and waveguide circuits. In long term, the method of cutting SIW components along magnetic wall to get HMSIW components can also play an important role in the future design, especially in size reduction and performance improvement of the circuits. Simulation results are in agreement with the measured data.

Compact Bandstop Half-Mode Substrate Integrated Waveguide Filter Based on a Broadside-Coupled Open Split-Ring Resonator

A shunt RLC resonant circuit obtained from a broadside-coupled open split ring resonator (BC-OSRR) is proposed. This BC-OSRR cell allows a parallel connection with planar waveguides. Hence, it has been applied to a half-mode substrate integrated waveguide (HMSIW) section. The analysis of the frequency response and electromagnetic field distribution of the HMSIW structure loaded with an appropriate BC-OSRR cell have shown two main behaviors. The first characteristic is a high-pass frequency response inherent to the HMSIW and the second is a transmission zero in the passband of the HMSIW, which is due to the resonance of the BC-OSRR cell. The First- and second-order prototypes have been designed and fabricated. The measured bandstop HMSIW filters using BC-OSRR achieve a 3-dB stopband bandwidth around 10% with more than 21-dB insertion loss. This BC-OSRR cell with low undesired radiation loss can be a new alternative for the implementation of compact bandstop filters in the planar technology.

Power Divider/Combiner using Half-Mode Substrate Integrated Waveguide (HMSIW) Technology with High Power and High Isolation

ABSTRACT A power divider/combiner using half-mode substrate integrated waveguide (HMSIW) and microstrip transmission lines with high isolation for high-power applications is presented. The design consists of a planar cavity, two 90° microstrip transmission lines, two matched loads, and one 180° microstrip transmission line. The cavity is fabricated using HMSIW structure and excited the TE101 mode at the centre frequency of 4.875 GHz. The external microstrip transmission lines and matched loads are added to improve the isolation between output ports. Moreover, the matched loads prevent the appeared heat loss in the substrate. The circuit behaviour is analysed based on the even and odd mode techniques, and the structure is simulated using a 3D EM simulator. The design is fabricated on a single-layer Rogers RO4003C, and a good agreement between the results of the simulation and measurement is observed. The measured results show that the proposed structure has the insertion loss of dB, and the isolation and output return loss better than 21.6 and 13.7 dB, respectively, when the return loss of the input port is better than 15 dB (4.8–4.95 GHz). This design has many advantages, such as low cost, low insertion loss, good return loss, good channels isolation, low profile, and compatibility with planar circuits.

Tunable Dual-Band Filter Based on Stub-Capacitor-Loaded Half-Mode Substrate Integrated Waveguide

This paper presents an original and simple approach to the design of dual-band bandpass filters (BPFs) using the proposed stub-capacitor-loaded half-mode substrate-integrated waveguide (HMSIW) structure. The stub-capacitor-loaded HMSIW structure is investigated and a set of analytical equations is provided for the determination of center frequency, transmission zero, coupling coefficient, and external quality factor. Dual-band BPFs can be achieved by loading stub capacitor on the two sides of the HMSIW structure. The two passbands can be designed separately and controlled independently. To validate this method, a class of dual-band filters with a wide range of fractional bandwidth ratios of the two passbands is designed. Finally, a dual-band filter, with each passband tuned only by one control voltage, is fabricated and measured. The results show that the first passband can be tuned in a frequency range from 1.85 to 2.67 GHz (36.4%) without any effect on the second passband. In the meantime, the second passband varies from 3.84 to 5.34 GHz (32.7%) without any effect on the first passband. Good return loss is observed within a wide tuning range.

Broadband Half Mode Substrate Integrated Waveguide Attenuator in 7.29–14.90 GHz

This letter presents a broadband half mode substrate integrated waveguide (HMSIW) attenuator. A resistive $\pi$ -network was built on the HMSIW structure to achieve respective target attenuation levels (1 dB, 2 dB, 3 dB, 4 dB, and 5 dB), where this network is comprised of a set of surface mount technology (SMT) passive resistors. The five different prototypes per attenuation level were evaluated (1–5 dB, 1 dB step) in a band of 7.29–14.9 GHz, and each prototype's simulation and measurement meet the good agreement.

Novel Capacitor-Loaded Substrate-Integrated-Waveguide Structure and Its Electronically Controlled Leaky-Wave Antenna Application

A capacitor-loaded slotted substrate-integrated waveguide structure is presented to realize a tunable composite right-/left-handed substrate-integrated waveguide structure. The capacitor-loaded slotted substrate-integrated waveguide structure is realized on a half-mode substrate-integrated waveguide structure to reduce the size. The inter-digital slots and varactor diodes are inserted to offer series-tunable capacitance of the composite right-/left-handed circuit model. A long slot is inserted to isolate DC bias, and the chip capacitors are mounted on the long slot to create a path for RF signal flow. Based on the tunable capacitor-loaded slotted substrate-integrated waveguide structure, an electronically controlled composite right-/left-handed leaky-wave antenna is designed. It is experimentally demonstrated that the direction of the main beam is continuously varied from +4° to −6° at 5.6 GHz as the bias voltage increases from 1 to 20 V.

Vivaldi antenna with reduced RCS using half‐mode substrate integrated waveguide

A bilateral Vivaldi antenna with reduced radar cross-section (RCS) is presented. A half-mode substrate integrated waveguide structure is first utilised in the low RCS Vivaldi antenna design. Compared with traditional antenna, the monostatic RCS of the proposed antenna can be reduced to as much as 24 dB without degradation of antenna performance.

Novel Balanced Bandpass Filters Using Substrate Integrated Half-Mode Waveguide

The contribution of this work is to propose novel balanced bandpass filters (BPFs) using the half-mode substrate integrated waveguide (HMSIW) and its size-reduced form, a folded HMSIW structure. The size of an HMSIW is about half of the substrate integrated waveguide (SIW) and the size of the folded HMSIW further reduces to 25%. Besides compactness, the proposed BPFs are attractive because the thru-via array needed for providing the side-wall effect is no longer required. In addition, the common-mode (CM) rejection of the HMSIW BPF is achieved from the non-coupling slots, caused by the PMC. The CM rejection of the folded HMSIW BPF is obtained by up-shifting the CM operating frequency far away from the differential-mode (DM) passband. Prototypes of the proposed circuits are fabricated and measured to present CM rejection levels larger than 40 dB over a wide frequency range and DM insertion losses around 2 dB in the passbands. Agreements between measured and simulated data are observed to validate the circuit design and performance.

Substrate integrated waveguide filters and mechanical/electrical reconfigurable half-mode substrate integrated waveguide filters

In this paper, novel evanescent mode substrate integrated waveguide (SIW) and half-mode substrate integrated waveguide (HMSIW) filters are proposed, and their applications to mechanical and electrical reconfigurable bandpass filters (BPFs) are studied. SIW and HMSIW loaded with coupled complementary split-ring resonators achieve forward electromagnetic wave transmission below the waveguide cutoff frequency due to evanescent wave amplification. The half-mode configuration of the proposed SIW BPF is an opening structure, and the proposed HMSIW BPF is suitable to load with control elements. The electric/magnetic coupling effects and frequency responses reconfigurable mechanics of the proposed HMSIW structure are studied based on lumped equivalent circuit model. By using floating capacitors with mechanical switches and PIN diodes loaded on the HMSIW resonators, two one-bit HMSIW 500 MHz mechanical and 300 MHz electrical reconfigurable BPFs are demonstrated.