Substrate Integrated Waveguide Research Articles

High Performance Multiple Passband Substrate Integrated Plasmonic Filters

We proposed a new variety of substrate integrated plasmonic filters (SIPFs) with multiple passband characteristics based on the concept of spoof surface plasmon polaritons (SSPPs). By etching a periodic interdigital structure array on the top metal layer of substrate integrated waveguide (SIW), we can achieve high-efficiency microwave SSPP transmission with an insertion loss of 1 dB in the passband of 7.4-12.5 GHz, and a high rejection level of 27 dB in the rejection bands. By introducing antisymmetric C-ring resonators (ASCRs) in the filter structure, the passband number and bandwidth of the filter can be flexibly manipulated. To validate the proposed design, four SSPP filters prototypes are fabricated and tested, showing good filtering performances with a high transmission coefficient ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{S}21\mathbf {&gt;}-$ </tex-math></inline-formula> 1 dB) and low reflection coefficient ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{S}11\,\,\mathbf { &lt; } - $ </tex-math></inline-formula> 12 dB) in their passbands, and a high rejection level over 15 dB between them. By changing the geometric parameters of ASCR, the number of passbands can be increased from 1 to 3, and the passband center frequency and bandwidth can be engineered accordingly. The proposed SSPP filters with good multiple passband characteristics may have great potential applications in microwave wireless integrated plasmonic circuits and communication systems.

Substrate Integrated Waveguide-Based Full-Duplex Antenna With Improved Out-of-Band Suppression

This brief presents a self-diplexing antenna with harmonic-suppression capability. The suggested antenna operates at 7.8 and 9 GHz and maintains a harmonic suppression of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.17f_{1}$ </tex-math></inline-formula> (where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{1}$ </tex-math></inline-formula> is the lower resonant frequency.) The isolation between two ports is more than 22 dB. The substrate-integrated waveguide (SIW) is used in the construction of the cavity-backed planar duplexing antenna. Starting from a microstrip patch antenna with undesirable high-frequency harmonics, a series of vias are used to suppress those harmonics. Finally, a slot (rotated over 45°) is used to bring the higher order mode to lower frequencies. Moreover, the size reduction in this design is achieved using capacitive slots. Consequently, the proposed antenna suppresses the second, third and fourth harmonics by using two pairs of slots and shorting pins. Besides having a low-profile and offering harmonic suppression, it provides independent frequency tuning in the operating frequency bands by means of capacitive slots. The proposed antenna is built and tested, displaying a reasonable match between the simulation and measurement performances, in this way validating the suggested concept.

Inkjet-Printed Ferrite Substrate-Based Vialess Waveguide Phase Shifter

Magnetically controlled waveguide-based phase shifters are desirable for their high performance, but are bulky and heavy, thus cannot be easily integrated with printed circuit board (PCB) based circuits. To tackle this, substrate-integrated waveguide (SIW) technology has been utilized, which brings the waveguide to a standard PCB, but requires large numbers of vias as well as multiple cavities in the substrate for ferrite slab placement. This implementation technique involves complex fabrication and yields a relatively low figure of merit (FoM). To alleviate this, we present the first completely vialess ferrite substrate-based waveguide phase shifter realized through low-cost inkjet printing technique. All the four sides of a yttrium iron garnet (YIG) substrate have been metalized through inkjet printing, allowing the fabrication of a conventional rectangular waveguide on a standard magnetic substrate. The prototype has been tested in symmetric as well as antisymmetric modes of biasing and peak FoMs of 160°/dB at 7.22 GHz and 332°/dB at 7.46 GHz have been measured, which are higher than those of the previously reported designs. This all-around inkjet printing approach can open the door to low-cost, integrable magnetic phase shifters with excellent RF performances.

Millimeter-Wave Monopulse Filtenna Array with Directive Dielectric Resonators

This paper presents a new millimeter-wave monopulse dielectric resonator (DR) filtering antenna (filtenna) array based on substrate-integrated waveguide (SIW) technology. The monopulse comparator realized by a square dual-mode (&lt;i&gt;TE&lt;/i&gt;&lt;sub&gt;102&lt;/sub&gt; and &lt;i&gt;TE&lt;/i&gt;&lt;sub&gt;201&lt;/sub&gt;) SIW feed cavity uses diagonal irises, of which couplings between the feed and next-stage cavities lead to almost identical filter responses for the sum and difference channels with compact size and a planar single-substrate structure. Both dielectric resonator antennas (DRAs) adopting &lt;i&gt;HEM&lt;/i&gt;&lt;sub&gt;133&lt;/sub&gt; mode for enhanced directivity are implemented with two filters based on SIW. The DR acts as the last resonator and the radiator in the filtenna. The prototype is designed at the Ka-band with a center frequency of 27.65 GHz and an operation bandwidth of 700 MHz. The measurement shows a 15-dB fractional bandwidth of 2.36%, a gain of 10.84 dBi for the sum channel, and a null depth of -15.6 dB for the difference channel.

Substrate Integrated Waveguide Based Cavity-Backed Circularly-Polarized Antenna for Satellite Communication

This article presents the methodology to design a single-fed circularly-polarized antenna with low front-to-back ratio (FBR). A circular-patch (CPatch) antenna has been incorporated within the rectangular-cavity, made of, substrate integrated waveguide (SIW). The size of the CPatch and the SIW cavity has been chosen appropriately, in a manner, that the both resonators dominant mode coincide. This arrangement has been adopted to realize the basic radiating unit with no surface-wave and the significantly lower FBR. The circularly polarization has been excited through shorting the periphery of CPatch radiator to the “one of the two metallic grounds” of this SIW cavity. The patch periphery has been shorted from two distinct points, separated by the quarter wavelength—over center frequency of working band. The antenna has been designed and manufactured over Rogers RT/Duroid 5880 substrate with dielectric constant (εr) of 2.2, loss-tangent (tan δ, at 10 GHz) of 0.0009, and substrate height of 0.508 mm. Southwest® end launcher (SEL) along with SIW-to-GCPW (Grounded Co-Planar Waveguide) transition has been used here to facilitate the measurement of antenna’s electrical and the radiation performance. The designed antenna’s impedance bandwidth and the 3 dB axial-ratio (AR) bandwidth is 9.5% and the 2.3%, respectively. It’s simulated and the measured peak gain, within working frequency band, is higher than 8.5dBic. The proposed antenna’s FBR is antenna is significantly lower than the conventional circularly-polarized antennas. Through comparative study, with work in open literature, it has been demonstrated that the designed antenna, based on proposed method, can a potential candidate for applicable in satellite and in the other spaceborne communication system’s module—at ground and in the space station.

Compact diplexer with high isolation based on mixed‐mode triangular substrate integrated waveguide cavities

AbstractA novel compact diplexer based on mixed‐mode isosceles right triangular (IRT) substrate integrated waveguide (SIW) cavities is presented. A dual‐mode IRT SIW junction cavity is direct‐coupled with two single‐mode IRT SIW cavities for lower and upper channels, respectively. The diplexer has two third‐order filtering channels, centred at 16 and 18.3 GHz with 400 and 422 MHz bandwidths. The in‐band measured return and insertion losses are 19 dB/1.3 dB in the lower band and 17 dB/1.36 dB in the upper band. Due to the orthogonality of TE102 and TE201 modes in dual‐mode IRT SIW cavity, high isolation (&gt;45 dB) between two channels is obtained. Besides, the proposed diplexer based on the triangular SIW cavity also has advantages of low cost and easy integration with other planar circuits.

Virtual antenna array for reduced energy per bit transmission at Sub-5 GHz mobile wireless communication systems

This paper presents an innovative technique to synthesize a virtual antenna array (VAA) that consumes less energy than conventional antenna arrays that are used in mobile communications systems. We have shown that for a specific spectral efficiency a wireless system using the proposed virtual antenna array consumes significantly less energy per bit (∼3 dB) than a wireless system using a conventional multiple-input multiple-output (MIMO) array. This means the adoption of the proposed VAA technology in smartphones, iPad, Tablets and even base-stations should significantly reduce the carbon footprint of wireless systems. The proposed VAA is realized by employing a pair of linear antenna arrays that are placed in an orthogonal configuration relative to each other. This orthogonal arrangement ensures the radiation is circularly polarized. The size of the standard radiating elements constituting the VAA were miniaturized using the topology optimization method. The design of the VAA incorporates substrate integrated waveguide (SIW) and metasurface technologies. The function of SIW in the design was twofold, namely, to reduce energy loss in the substrate on which the VAA is implemented, and secondly to mitigate unwanted electromagnetic interactions between the neighboring radiating elements and thereby enhancing isolation which otherwise would degrade the radiation characteristics of the array. Metasurface technology served to effectively increase the effective aperture of the array with no impact on the footprint of the array. The consequence of SIW and metasurface technologies was improvement in the gain and radiation efficiency of the array. The proposed four orthogonal 4-element VAA covers the entire sub-5 GHz frequency range, and it radiates bidirectional in the azimuth plane and omni-directional in the elevation plane. Moreover, it is relatively easy to design and fabricate. The proposed VAA has dimensions of 0.96λ0 × 0.96λ0 × 0.0016λ0 at mid-band frequency of 3 GHz. VAA has a measured gain of 25 dBi and radiates with 90% efficiency. The average isolation between the linear arrays constituting the virtual array is better than 27 dB.

Wearable coupled-quarter-mode SIW antenna platform with hybrid kinetic and ambient-light energy harvesting

As key enablers for smart fabric interactive textile (SFIT) systems, textile antenna systems and platforms need to be energy-efficient, low-profile and should guarantee a stable wireless body-centric communication link. Using multiple energy harvesters on and in the antenna platform is highly recommended to enable autonomous SFIT systems. Different sensors could be added to the system for monitoring the environmental and/or biophysical parameters of rescue workers, military personnel, and other safety workers. Therefore, a wearable coupled-quarter-mode (coupled-QM) substrate-integrated waveguide (SIW) antenna with optimally, seamlessly integrated hybrid kinetic and ambient-light energy harvesters is proposed. Two QM cavities are coupled via a non-resonant slot to create a compact antenna covering the [2.4; 2.4835] GHz Industrial, Scientific and Medical (ISM) band. The antenna platform fully consists of textile materials, being protective rubber foam and copper taffeta, enabling its unobtrusive integration into protective clothing. A novel, compact way of deploying a kinetic energy harvester inside the substrate, combined with flexible power management electronics on the antenna feed plane and a flexible ambient-light photovoltaic cell on the antenna plane, is proposed. The integrated antenna platform exhibits a measured impedance bandwidth of 307 MHz, a radiation efficiency of 88.57% and maximum gain of 3.74 dBi at 2.45 GHz. Wearing the antenna platform around a person’s wrist resulted in an average harvested power of 229.8 µW when walking in an illuminated room.

Design of Miniaturised Circular Polarisation-Reconfigurable and Frequency Agile Slow-Wave SIW Based Microstrip Antenna for Wireless Applications

ABSTRACT Maintaining acceptable radiation performance over the entire operation bandwidth is a significant challenge in development of a miniaturized reconfigurable antenna To address this issue, a new Substrate Integrated Waveguide (SIW) based reconfigurable antenna using slow wave structure is presented in this study. The proposed SIW antenna is based on a layered construction with metallic blind vias connecting to ground plane of SIW. The multi-layer structure of SIW with blind vias helps to separate magnetic and electric fields in the SIW cavity. Thus, a slow wave effect is also utilized and it leads to 36% reduction in the antenna size as compared to conventional SIW cavity. To attain the polarization and frequency reconfiguration, a cross slot is introduced in the top metallic layer of the SIW cavity and four PIN diodes are connected into the cross-slot arms. Experimental results exhibit frequency reconfigurability in different operating regions with resonant frequencies 4.35, 5, 5.8, 6.4, and 9.6 GHz. The polarization reconfigurability of the proposed antenna is achieved at 5 GHz with LP/RHCP/LHCP. The proposed antenna exhibits 3-dB axial ratio bandwidth of 4.8 to 5.2 GHz with peak gain of 4.2 dBi.

Microwave atmospheric pressure plasma jet generated from substrate integrated waveguide resonator

AbstractA microwave atmospheric pressure plasma jet (MW‐APPJ) generator based on a substrate‐integrated waveguide (SIW) resonator is proposed. A thin, straight plasma needle with a length of 9 cm could be obtained. Higher than 90% of microwave feeding efficiency is obtained under a wide range of gas flow rates without a microwave matching network. As the gas flow increased from 1 to 14 L/min, a transition from laminar to turbulent mode is observed in the plasma jet's morphology. Furthermore, a preliminary surface treatment was tested for the device. The polyimide film became super hydrophilic after a 5‐min treatment with the developed SIW‐based plasma generator. Generally, the SIW‐based MW‐APPJ is low‐cost, electrodeless, and low‐profile along the plasma jet length direction.

High Gain and Wideband Antenna-in-Package Solution Using Fan-Out Technology

AbstractThe technology of fan-out wafer level packaging (FOWLP) has been widely adopted for millimeter wave antenna-in-package (AiP) system integration with low interconnection parasitic parameters. Present AiP solutions using FOWLP technology generally form antenna pattern on redistribution layer, which brings design inconvenience. In our work, a low-cost printed circuit board RO4350B laminate for substrate-integrated waveguide (SIW) antenna with a relatively large size is integrated, forms a three-dimensional stacked structure. The AiP employs a right-angle transition board embedded in epoxy molding compound (EMC), which transmits millimeter-wave signal to the SIW antenna stacked on the backside of EMC. The SIW antenna consists of 4 × 4 radiation slots with modified magneto-electric dipole for bandwidth enhancement. The measured gain is 14dBi at 60 GHz with bandwidth beyond 55–65 GHz. The three-dimensional AiP structure improves heat dissipation, no extra thermal design is needed for applications under 0.5 W mm-wave chip power consumption. The AiP module is manufactured and measured on the test board. The proposed approach is a convenient solution for wide band and high gain millimeter wave AiP system integration.

Development and evaluation of microwave microfluidic devices made of polydimethylsiloxane

A transparent, optically observable microfluidic device for microwave-induced chemical reactions using 24.125 GHz ISM band incorporating was developed. The microfluidic channels can pass through gaps in the post-wall waveguide. The post-wall waveguide allows microwave irradiation to be applied to designed area of the microfluidic channel. In this study, Polydimethylsiloxane (PDMS), commonly used in microfluidic devices, was used as the microwave waveguide material. A glass plate sputtered with indium tin oxide was used to shield microwave leakage to the top and bottom. 4 W of microwave input power was used to heat ethylene glycol, which is used as a solvent in chemical synthesis, in the channels of the fabricated device, and a temperature rise to 100 °C was observed in 70 s. We believe that the use of PDMS as a waveguide material will facilitate observation during microwave irradiation using optics and combination with other microreactors.

Design of low profile wideband high power waveguide to substrate integrated waveguide coupler

AbstractThis paper presents a new wideband waveguide substrate integrated waveguide (SIW) coupler with maximum deviation of ±0.5 dB in a 7.5–12.25 GHz bandwidth (48% fractional bandwidth). Proposed coupler consists of the standard WR90 waveguide and single layer/double clad SIW printed circuit board (PCB) which is placed crosswise on the waveguide. Proposed three port coupler (isolated port was ended with match load) has a two coupling level (average of coupling in 8–12 GHz frequency range) of 43.2 and 58.3 dB, which is correspond with the hole diameter of 3.5 and 3 mm, respectively. The main contribution of this work is based on the hybrid techniques of SIW and RWG for coupler design in the high power microwave application. Validation of the simulation results with measurement one proves that the proposed X‐band waveguide to SIW coupler is a good candidate for use in high power industrial/commercial applications.

A Microwave Pressure Sensor Loaded with Complementary Split Ring Resonator for High-Temperature Applications

A passive substrate integrated waveguide (SIW) sensor based on the complementary split ring resonator (CSRR) is presented for pressure detection in high-temperature environments. The sensor pressure sensing mechanism is described through circuit analysis and the electromagnetic coupling principle. The pressure sensor is modeled in high frequency structure simulator (HFSS), designed through parameter optimization. According to the optimized parameters, the sensor was customized and fabricated on a high temperature co-fired ceramic (HTCC) substrate using the three-dimensional co-fired technology and screen-printing technology. The pressure sensor was tested in the high-temperature pressure furnace and can work stably in the ambient environment of 25-500 °C and 10-300 kPa. The pressure sensitivity is 139.77 kHz/kPa at 25 °C, and with increasing temperature, the sensitivity increases to 191.97 kHz/kPa at 500 °C. The temperature compensation algorithm is proposed to achieve accurate acquisition of pressure signals in a high-temperature environment.

Design of 60 GHz millimeter‐wave SIW antenna for 5G WLAN/WPAN applications

AbstractBroadband millimeter Wave (mmWave) transmission at the 60 GHz band is a great prospect to meet the demanding high data rate requirements of future wireless personal area network (WPAN) and wireless local area network (WLAN) 5G networks. This paper proposes a single layer H‐plane sectoral horn mmWave antenna at 60 GHz using substrate integrated waveguide (SIW) technology for the future high‐speed short range WPAN and WLAN networks. The benefits of the proposed antenna are high gain, low cost, small size, and ease of integration with other planar circuits. The proposed SIW horn is constructed with RT/duroid 5880 substrate, which has a relative permittivity and loss tangent with a thickness of 0.508 mm. The novelty of this work is; a wider bandwidth is achieved by adding striplines at the horn aperture to match the antenna with air and to increase the antenna operating bandwidth. In addition, the antenna gain is improved by adding a dielectric lens with the striplines at the radiating end. During these steps, the antenna parameters are tuned and optimized to achieve the best results as compared to related previous studies. The proposed antenna's performance is analyzed in terms of gain, return loss (S11) and radiation pattern at a frequency of 60 GHz. Simulation results are carried out by using industry standard software, Computer Simulation Technology (CST) microwave studio. The designed antenna achieves a peak gain of 13 dB and impedance bandwidth when , 8.6 GHz (13.688%) for the reflection coefficient of . The results show that the proposed antenna achieves stable tunable 60 GHz frequency performance, which makes it feasible to deploy in WLAN/WPAN operating in mmWave bands.

Dispersion engineering of spoof plasmonic metamaterials via interdigital capacitance structures.

This work presents an approach to realize the dispersion engineering of spoof plasmonic metamaterials with controllable cutoff frequencies. Interdigital capacitance structures are applied to construct the unit cells. Dispersion properties are firstly analyzed to investigate the effects of interdigital capacitance, and the influence of the geometrical parameters of the proposed unit cell on the cutoff frequencies is studied. Then, a spoof surface plasmon polariton (SSPP) transmission line (TL) is developed based on the proposed unit cell together with a smooth transition. The matching principles of the transition are explained by the dispersion curves and the normalized impedance of the corresponding matching unit cells. Finally, the transmission characteristics of the TL are simulated and measured to validate the feasibility of the proposed strategy. Both the lower and upper cutoff frequencies can be tuned jointly by the extra degrees of freedom provided by the interdigital capacitance structures. In comparison with designs based on a substrate-integrated waveguide (SIW), the proposed strategy can reduce the transversal dimension by a factor of two under the same conditions. This work can greatly accelerate the development of versatile microwave integrated circuits and systems based on spoof plasmonic metamaterials.

H-plane SIW horn antenna with enhanced front-to-back ratio for 5G applications

Millimeter-wave (mmWave) antennas are indispensable components in the fifth-generation (5G) wireless communication systems. With the inherent advantages of integration capability, substrate integrated waveguide (SIW) antenna is an excellent choice for applications in the mmWave frequency bands. However, reflection losses occur at dielectric-filled thin apertures of SIW antennas. These reflections can be overcome by impedance matching between the aperture and the free space. In this study, we introduce an mmWave SIW horn antenna having impedance matching transitions (IMTs) across the horn's aperture width. The designed antenna, operating in the 24-28 GHz band, is simulated with a full-wave analysis tool. The simulation results of the modified SIW horn have been confirmed by the experimental results and shown to be satisfactory. The IMTs result in an enhancement of the front-to-back ratio (FTBR). The modified SIW horn antenna with a novel printed transition achieves sidelobe levels (SLLs) of better than ?9 dB at 27 GHz, with an enhanced FTBR above 15 dB. In the 24?28 GHz band, the antenna has a reflection coefficient variation of better than ?10 dB.

A Survey on Substrate Integrated Waveguide Filters; Design Challenges and Miniaturizing Techniques for the 5G

It is believed that the substrate integrated waveguide (SIW) technology represents the emergent and the most favorable contender for the advancement of the antennas, filters and the other circuit elements operational in the region of microwave as well as the millimeter wave frequencies. SIW layouts offer the advantages of the cost-effective integration of traditional transmission lines and retain the benefits of the classical metallic waveguides, in particular high-quality factors, low losses and the large power handling capability with the self-sufficient electrical shielding. In this paper, a review of the fundamental and operational theory of the SIWs has been discussed and presented. Moreover, the challenges and design considerations in terms of microwave and millimeter filters, the different miniaturization techniques and the most important; its application and implementation for the next-generation 5G communications and beyond has been presented.

A Single-Layer Filtering Antenna With Two Controllable Radiation Nulls Based on the Multimodes of Patch and SIW Resonators

A single-layer filtering hybrid antenna with low profile and high selectivity is presented. The proposed antenna is composed of a triangular patch and a substrate integrated waveguide (SIW) cavity with triangular slot and U-shaped slot etched on the top surface. The patch is embedded in the triangular slot. Four modes can be generated by the hybrid structure. That is, the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> mode of the patch, the right half-TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> , the modified right half-TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> and the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.5, 1</sub> modes of the SIW cavity are selected. By merging the four modes into a single passband, the impedance bandwidth is broadened, and the frequency selectivity is enhanced. There are two radiation nulls at the lower and upper edges of the passband, which can be controlled independently. In addition, part of the shorting pins surrounding the SIW cavity is truncated to decrease the operating frequency and increase the out-of-band rejection. The measured –10 dB impedance bandwidth ranges from 3.44 to 3.62 GHz with sharp frequency selectivity and more than 18 dB out-of-band suppression level.

Wideband and low‐loss transition from low‐temperature co‐fired ceramic laminated waveguide to subminiature coaxial connector for millimetre‐wave applications

This letter presents a novel transition scheme from laminated waveguide (LWG) to subminiature coaxial connector with wideband and low-loss performance. The laminated waveguide is achieved using multilayer low-temperature co-fired ceramic (LTCC) technology. In the conventional transition scheme, a length of grounded coplanar waveguide (GCPW) is used to connect the LWG and coaxial connector to obtain a wide bandwidth, which increase the transition size and radiation loss, especially in millimetre-wave (MMW) band. To realize a compact and low-loss LWG-to-coaxial connector transition, the GCPW line is removed and the whole LTCC transition structure is designed underneath the coaxial connector. Moreover, two stages of waveguide step are introduced to constrain the electromagnetic field in the transition for lower radiation loss, which also contributes to the wideband impedance matching. The back-to-back transition is designed and fabricated with LTCC technology to validate the proposed transition scheme. A measured bandwidth of 44% from 27.3 to 42.9 GHz is achieved under |S11| < −15 dB and the insertion loss of single transition is about 0.4 dB.