Quarter-mode Substrate Integrated Waveguide Cavity Research Articles

Wide stopband QMSIW diplexer with large frequency ratio and flexible specification

AbstractIn this letter, a wide stopband quarter‐mode substrate‐integrated waveguide (QMSIW) diplexer is proposed. By using coupling feeding lines and QMSIW cavities, the two passbands of the diplexer can be controlled independently by their respective QMSIW bandpass filters. In comparison to other counterparts, the proposed diplexer provides flexible passband specification, compact size, and high isolation. The design exhibits a wide 20‐dB stopband up to 3.2f0, a frequency ratio of 1.6, and a high isolation level larger than 42.2 dB across the passbands.

Self-triplexing HMSIW antenna with enhanced isolation and extremely low frequency ratio

A self-triplexing antenna based on half-mode substrate integrated waveguide (HMSIW) cavity is proposed in this paper. The HMSIW cavity is designed as a combination of two eighth-mode substrate integrated waveguide (EMSIW) cavities and a single quarter-mode substrate integrated waveguide (QMSIW) cavity. The self-triplexing property is achieved by placing a narrow longitudinal slot on one of the EMSIW cavities and an annular cut on the QMSIW cavity. The proposed triplexer antenna operates at three distinct yet closely spaced frequencies 3.85 GHz, 4.12 GHz and 4.54 GHz with an extremely low frequency ratio (FR) of 1.18. The three operating bands are 3.82 - 3.88 GHz, 4.08 – 4.14 GHz and 4.51 – 4.57 GHz. The operating frequencies can be tuned independently by varying the dimensions of the slots. A minimum port isolation of 29 dB is achieved between the three cavities that contributes for self-triplexing property. The measured gain at three resonant frequencies is 6.02, 5.74 and 6.35 dBi, respectively. The proposed HMSIW self-triplexing antenna occupies a very small area of 0.14 λ02 (λ0 is the free space wavelength at the lowest operating frequency) and it is extremely useful for fixed wireless access and point-to-point commercial microwave applications.

A Quad-Band Shared-Aperture Antenna Based on Dual-Mode Composite Quarter-Mode SIW Cavity for 5G and 6G with MIMO Capability

This study introduces a new design for an ultra-compact shared-aperture antenna utilizing a quarter-mode substrate integrated waveguide (QMSIW) cavity. The proposed antenna operates as a 4 × 4 multi-input multi-output (MIMO) system in three 5G/6G millimeter-wave (MMw) bands, while functioning as a single element antenna for a 5.5 GHz wireless fidelity Microwave (Mw) band. The antenna comprises four QMSIW cavity resonators; each QMSIW is loaded with dual slots to produce tri-band MMw operation at 28 GHz, 38 GHz, and 0.13 THz. The four cavities are arranged to reuse the entire aperture by creating a conventional open-loop antenna that operates at a frequency of 5.5 GHz. Simulation, measurement, and co-simulation results show that the proposed antenna has a quad-band operation and exhibits favorable characteristics. The measured scattering parameters validate the simulated ones over the four bands under consideration. The lowest values of the measured total radiation efficiencies are 80%, 73%, 62%, and 72% (co-simulation) within the four covered bands, respectively. The antenna peak gains are 1.8 to 1.85 dBi, 4.0 to 4.5 dBi, 4.3 to 4.5 dBi, and 6.5 to 6.6 dBi within the covered bands. Furthermore, the design satisfies MIMO and diversity conditions (envelope correlation coefficient and branch power ratio) over frequency bands of operation. All excellent results are achieved from an ultra-compact size in terms of footprint area (0.018λ02), where λ0 represents the free space wavelength at 5.5 GHz. The antenna boasts an excellent reuse aperture utilization efficiency (RAU) of 92% and a large ratio frequency of 23, making it an ideal candidate for compact devices. With its superior performance, the proposed design is well-suited for a range ofs wireless communication systems, including mobile devices and the Internet of Things.

Miniaturized Quarter-Mode SIW Filters Loaded by Dual-Mode Microstrip Resonator With High Selectivity and Flexible Response

A novel miniaturized multilayer quarter-mode substrate integrated waveguide (QMSIW) filter with high selectivity and wide stopband is proposed. First, an innovative multilayer dual-mode microstrip resonator is proposed to couple the QMSIW resonators located at the upper and lower substrate layers. The combination of the dual-mode resonator with the two QMSIW cavities leads to a fourth-order filtering response. Then, the coupling iris is opened at the position, where the magnetic field distribution in the QMSIW cavity achieves a peak value. Finally, sharp skirt is obtained by composing the modified box-like topology. In addition, different responses could be achieved by changing the position of the coupling iris, resulting in a wide stopband and flexible response. The size of the filter is also reduced through the multilayer QMSIW configuration and miniaturized multilayer dual-mode microstrip resonator.

A W-Band Compact Substrate Integrated Waveguide Bandpass Filter With Defected Ground Structure in CMOS Technology

This brief proposes the first on-chip bandpass filter (BPF) based on substrate integrated waveguide (SIW) for W-band applications. Slot-loaded, folded ridge and quarter mode technology is used to reduce the cavity size. The coupling characteristic of two folded ridged quarter mode substrate integrated waveguide (QMSIW) cavities implemented in CMOS technology is investigated. A simplified equivalent lumped-element circuit model of the proposed wide-band BPF approach is provided and applied to study the coupling characteristic of slot-loaded folded ridged QMSIW cavity. Then, a novel coupling method using a defected ground structure is proposed to realize a proper coupling intensity for BPF design. Finally, the proposed BPF design is implemented in a commercial complementary metal-oxide-semiconductor (CMOS) technology, fabricated, and measured. The active size of the proposed cavity resonator is only 405 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}\,\,\times185\,\,\mu \text{m}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.22{\lambda }_{\mathrm{ g}} \times 0.1 \lambda _{\mathrm {g}}$ </tex-math></inline-formula> ), and the measured insertion loss ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert|\text{S}_{21}~\vert|$ </tex-math></inline-formula> ) is 3.15 dB with a central frequency of 85.5 GHz.

Ultra-compact self-diplexing antenna based on quarter-mode substrate integrated waveguide with high isolation

AbstractThis article presents the design of an ultra-compact cavity-backed self-diplexing antenna with high isolation employing quarter-mode substrate integrated waveguide (QMSIW). The proposed antenna is constructed by using QMSIW, slot, and two 50Ω feed lines. Two eighth-mode cavity resonators are designed by inserting a slot on the top side of the rectangular substrate integrated waveguide to operate at 2.6 and 4.9 GHz for long-term evolution and public safety band applications, respectively. The proposed design allows to tune any frequency band independently by keeping other bands unaltered. The size of antenna is ultra-compact, due to the use of QMSIW cavity. The isolation between two ports is &gt;35 dB. The antenna achieves 5.34 and 5.68 dBi peak gains at 2.6 and 4.9 GHz, respectively. The efficiency of the antenna is &gt;85% at both frequency bands. The antenna provides more than 20.9 dB front-to-back-ratio and better than 21 dB separation between co-to-cross polarization levels. The designed antenna is validated through fabrication and measurement.

Design of highly compact self‐diplexing Y‐shaped slot antenna employing quarter‐mode substrate integrated waveguide

This communication reports the design of highly compact cavity-backed self-diplexing Y-shaped slot antenna for high-isolation employing quarter-mode substrate integrated waveguide (QMSIW). The proposed antenna is built by using QMSIW, Y-shaped slot and two 50 Ω feed lines. Two unequal radiating apertures are developed by inserting an Y-shaped slot on the top side of the rectangular SIW for radiation at 3.9 and 4.9 GHz for long term evolution (LTE) and public safety band (PSB) applications, respectively. By keeping another band unaltered, the proposed antenna allows any frequency band to be tuned independently. The size of antenna is highly compact due to the use of QMSIW cavity. The isolation between two ports of the antenna is greater than 34 dB. The antenna achieves 5.43 and 5.85 dBi peak gains at 3.9 and 4.9 GHz, respectively. On both the frequency bands, the antenna efficiency is greater than 85%. The antenna has a front-to-back-ratio of more than 20.6 dB and a separation from co-to-cross polarization level of more than 21 dB. Through manufacture and measurement, the designed antenna is validated.

SIW Cavity Backed Self-Diplexing Tunable Antenna

This communication presents a compact quarter-mode substrate integrated waveguide (QMSIW) cavity-backed self-diplexing tunable antenna. An open-ended slot is used to split the circular half-mode SIW (HMSIW) cavity resonator into two QMSIW cavity resonators. A varactor diode-loaded stub is added with each QMSIW resonator to achieve miniaturization and resonant frequency tuning. The miniaturization and tunability technique is demonstrated in a stand-alone QMSIW resonator and also in a QMSIW based self-diplexing antenna. The antenna is simulated, optimized, and subjected to practical testing inside a rectangular device. The device is treated as a quasi-receiver/transmitter, which consists of electronic circuitry and the proposed antenna. The resonant frequencies can be independently tuned by changing the values of the varactor diodes connected with each resonator. The simulated and measured results confirm that the proposed antenna can be tuned from 3.77 to 4.59 and from 4.96 to 6.1 GHz in the lower and higher frequency bands, respectively. The isolation between the two resonators in both bands is always better than 21 dB. The measured gains vary from 4.85 to 5.87 and 4.87 to 6.5 dBi in the lower and higher frequency bands, respectively. The proposed design shows stable and unidirectional radiation patterns in all tuning cases in both bands. The proposed self-diplexing tunable antenna is a competitive choice in compact and spectral-efficient radio frequency (RF) front ends where tuning is necessary for the efficient use of the frequency spectrum.

QMSIW-Based Single and Triple Band Bandpass Filters

This brief proposes compact and planar substrate integrated waveguide (SIW)-based filters for single and triple band operations using two quarter-mode SIW (QMSIW) cavities. Two miniaturized QMSIW cavity resonators (QMSIWCRs) are capacitively coupled. Miniaturization in the QMSIWCR is achieved by adding an arc-shaped slot and a rectangular open-ended stub at the closed-end of the QMSIWCR. In the triple band bandpass filter (BPF), a capacitor is added to the open-ended side of the stub to enhance impedance matching at the higher modes. It has the centre frequencies of 2.1, 3.98 and 6.6 GHz with an insertion losses (ILs) of 0.93, 0.98, and 1.2 dB at the lower, middle and upper passband, respectively. Moreover, the measured fractional bandwidths (FBWs) are 16.97, 8.77, and 8.42% at the lower, middle and upper passband, respectively. Two rectangular slots are etched on the upper layer of the cavity to suppress the second mode and reduce coupling of the third mode; this realizes a single-band filter with an improved upper stopband response. It has the centre frequency of 2.1 GHz with a wide upper stop-band response, having a rejection level of 20 dB up to 3.19f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> . The operation of filter is additionally discussed and verified by means of a lumped element equivalent circuit model and experimental results. The proposed filters are suitable for integration with other planar radio-frequency (RF) components due to their compact sizes, low ILs, planar structures, multiple transmission zeros (TZs) and adequate bandwidths.

Compact, Wide Stopband, Shielded Hybrid Filter Based on Quarter-Mode Substrate Integrated Waveguide and Microstrip Line Resonators

A novel miniaturized bandpass filter (BPF) with high stopband rejection based on a hybrid structure is proposed with shielded quarter-mode substrate integrated waveguide (QMSIW) and microstrip technologies. The shielded QMSIW cavity provides a high-quality ( $Q$ ) factor with substantial size reduction. This filter exhibits flexible response with four poles and two controllable transmission zeros (TZs) by incorporating two quarter-wavelength microstrip resonators into two back-to-back QMSIW resonators. The working principles for higher order mode suppression and filter coupling topology are carefully illustrated by eigen-mode simulation, coupling matrix, and field distribution analysis, respectively. Compared with the reported works, the proposed four-order BPF demonstrates advantageous features in terms of a compact size of $0.62\,\,\lambda _{0}\times 0.62 \,\,\lambda _{0}$ , a low insertion loss of 1.2 dB, a wide passband (22.7%), and a high stopband rejection (better than 36 dB).

A Single-Layer Circularly Polarized Antenna With Improved Gain Based on Quarter-Mode Substrate Integrated Waveguide Cavities Array

In this letter, a single-layer right-hand circularly polarized (RHCP) antenna with low-profile and improved gain based on quarter-mode substrate integrated waveguide (QMSIW) cavities array is proposed and experimentally validated. The proposed antenna consists of a central microstrip patch and four QMSIW cavities with the same dimensions, which are directly cascaded to the central patch. The E-field distribution of the proposed structure is similar to that of a circular SIW cavity working in the high-order TM120 mode. Due to the in-phase equivalent magnetic currents array formed by the fringing electric field of the radiation edges, a high RHCP gain with very low cross polarization in the broadside is achieved. Because of the high-order working mechanism, the antenna can be fed by a coaxial probe directly without any complex power distribution network. Measured RHCP gain of the antenna is up to 10.4 dBi at the center frequency point 5.78 GHz, which is in good agreement with the simulated results.

Dual‐functional QM SIW cavity integrating two‐element MIMO antenna and second‐order bandpass filter

A quarter-mode (QM) substrate-integrated-waveguide (SIW) cavity is designed as a dual-functional component. By etching three slots, four sub-cavities are formed and then two of them with the same size are individually fed by a coaxial port. Three resonating frequencies are excited in the single QM SIW cavity. One of them can radiate cavity energy input by these ports into free space, implying a two-element multiple-input-multiple-output (MIMO) antenna, whereas the other two can transmit energy from one port to the other port, indicating a second-order bandpass filter. Moreover, antenna isolation and filter bandwidth can be adjusted to a certain degree. A prototype with the overall size of 0.40λ0 × 0.40λ0 × 0.02λ0 has been fabricated. The integrated bandpass filter demonstrates the measured center frequency of 3.8 GHz and operating bandwidth of 32 MHz while the integrated MIMO antenna exhibits the frequency of 3.4 GHz, bandwidth of 67 MHz, port isolation of 18.0 dB, radiation gain of 4.0 dBi, and envelope correlation coefficient of 0.25.

Wideband and Wide-Angle FSS Using Loop Slotted Hybrid Quarter-Mode Substrate Integrated Cavity With Two Independently Controllable Poles

A wideband and wide-angle frequency selective surface (FSS) is proposed in this communication. The periodic element consists of a quarter-mode substrate integrated waveguide (QMSIW) cavity surrounded by two identical loop slots located on the top and bottom layers of the cavity. Two transmission poles and one transmission zero are caused by the fundamental mode in the QMSIW cavity, the slot mode, and the coupling between them, respectively. By precisely tuning the dual-mode configuration, the proposed FSS shows a wide passband with a good transmission efficiency and a rapid roll-off at the high side of the operation band due to the transmission zero. With the QMSIW-based miniaturized elements, the FSS is also insensitive to a large angle of incidence. Thanks to the novel structure, several higher order modes close to the target band are suppressed, making the parasitic passband far away from both sides of the designed band. To verify the advantages, a prototype operated at 10 GHz is fabricated and tested. The measured results show a wide passband performance with the 1/3 dB relative bandwidths of 34%/49% for normal incidence, which agree well with the simulated results. Besides, the 3 dB bandwidth still remains 23% for the incident angle of 60°.

Miniaturized Folded Ridged Quarter-Mode Substrate Integrated Waveguide RF MEMS Tunable Bandpass Filter

This paper presents a miniaturized RF MEMS tunable bandpass filter design developed by application of folded ridged quarter-mode substrate integrated waveguide cavity. Using packaged RF MEMS SP4T chips, a switchable reactive loading is applied to the folded ridged quarter-mode substrate integrated waveguide cavity, tuning the resonance frequency. Overall miniaturizations of 70.3% and 78.8% are achieved for inductively- and capacitively-loaded filters compared to an RF MEMS tunable filter using half-mode substrate integrated waveguide. Here, an analysis of inductive or capacitive loading along with their advantages and disadvantages are discussed. Two different two-pole folded ridged quarter-mode substrate integrated RF MEMS tunable bandpass filters are designed and measured. The first prototype employing inductive loading achieves 4.4% tuning range at a center frequency of 1.713 GHz, insertion loss of 3.10-3.92 dB, and return loss greater than 15 dB for all tuning modes. The second prototype employing capacitive loading is measured with a 35.2% tuning range at a center frequency of 865 MHz, insertion loss of 1.6-4.3 dB, and return loss greater than 10 dB for all tuning modes. The reported performance and extreme miniaturization of folded ridged quarter-mode substrate integrated waveguide cavities shows great promise for their application in tunable filter design.

In brief

PAGE 589 Swarm reinforcement learning that extends standard Q-learning to multi-agent systems via the development of a real-time swarm algorithm has been presented by a large collaboration of researchers from Italy. The novel approach achieves a substantial speed increase over standard learning methods and promises enhanced learning performance in more complex environments. PAGE 573 Researchers from Belgium and China jointly present a multi-functional dual band frequency reconfigurable antenna with pattern diversity for use in wireless communication systems. The antenna consists of a composite right/left-handed transmission line inspired structure, with simulations and experiment validating the new concept. Optimal maze solution. PAGE 619 A team of researchers from Japan have produced a neural optical implant which is monolithically integrated with a micro-light-emitting diode (µLED), a micro-photodiode, and a polymer waveguide. This tool can suppress the influence of temperature while making good use of the advantages offered by the LED, with the µLED placed outside, but still able to optically stimulate, the brain. Metamaterial antenna prototype. PAGE 599 Sequence pairs with good correlation can be applied in many practical systems, with a pair of Chinese researchers having constructed a class of sequence pairs by interleaving two sequences derived from the Fermat quotient. The produced sequence pairs subsequently have almost perfect correlation. SEM image of substrate after deep RIE etching. PAGE 574 Researchers from China have presented a compact self-isolated MIMO antenna system based on a quarter-mode substrate integrated waveguide cavity. With the advantages of compact size, high isolation, and good radiation performance, the proposed antenna has many applications in wireless communications. A section of the cross-correlation proof employed. Half-mode electric field distribution.

Compact QMSIW-based antenna with different resonant frequencies depending on loading of metalized vias

AbstractIn this work, simple, low profile, compact quarter-mode substrate-integrated waveguide (QMSIW)-based antennas are proposed for Wireless Local Area Network (WLAN) at 5.2/5.5 GHz and Wireless Body Area Network (WBAN) at 5.8 GHz, respectively. By implementing QMSIW technique, the electrical size of the antenna is reduced up to 1/4th of the conventional circular SIW cavities. Thanks to the quarter mode concept, the antenna size is reduced significantly by preserving its dominant mode. The resonant frequency of the dominant mode TM010 is independently tuned at 5.2, 5.5, and 5.8 GHz after loading the QMSIW cavity with metalized via holes, subsequently. The on-body performance of the antenna is verified on pork tissues at 5.8 GHz and it is found to be insensitive with respect to surroundings. The measured gain and simulated efficiency of the proposed antenna at 5.8 GHz in free space are 4.8 dBi and 92%, while in the proximity of pork tissues values are 3.25 dBi and 57%, respectively. Moreover, the measurement results demonstrate a good matching with the simulation results.

Dual-Band (28,38) GHz Coupled Quarter-Mode Substrate-Integrated Waveguide Antenna Array for Next-Generation Wireless Systems

A novel dual-band substrate-integrated waveguide (SIW) antenna array topology is proposed for operation in the 28 and 38 GHz frequency bands. Four miniaturized quarter-mode SIW cavities are tightly coupled, causing mode bifurcation, and yielding an antenna topology with four distinct resonance frequencies. A pair of resonances is assigned to both the 28 and 38 GHz band, achieving wideband operation in both frequency ranges. Moreover, owing to the exploited miniaturization technique, an extremely compact array topology is obtained, facilitating easy and straightforward integration. The computer-aided design process yields a four-element antenna array that entirely covers the 28 GHz band (27.5–29.5 GHz) and 38 GHz band (37.0–38.6 GHz) with a measured impedance bandwidth of 3.65 and 2.19 GHz, respectively. A measured broadside gain of 10.1 dBi, a radiation efficiency of 75.75% and a 3 dB beamwidth of 25° are achieved in the 28 GHz band. Moreover, in the 38 GHz band, the measured broadside gain amounts to 10.2 dBi, a radiation efficiency of 70.65% is achieved, and the 3 dB beamwidth is 20°.

A Triple-Mode Bandpass Filter With Controllable Bandwidth Using QMSIW Cavity

A compact triple-mode bandpass filter using a modified quarter-mode substrate integrated waveguide (QMSIW) cavity is presented. It is realized by exploiting the first three resonant modes of the QMSIW cavity. Specifically, the dominant mode (TE101) is shifted toward the second resonant mode (TE202) through the perturbation induced by the metallized via-holes array. The resonant frequency of the third resonant mode (TE303) is lowered toward the TE202 mode owing to the capacitive loading effect of the loaded circular conductive posts array. In this way, by adjusting the via-holes array and the conductive posts array, the resonant frequencies of the first and third resonant modes can be independently tuned while the second resonant mode remains unchanged. As a result, the bandwidth of the resulting filter can be flexibly controlled at a preassigned center frequency. Moreover, to suppress the spurious frequencies generated by the higher order modes, three cascaded defected ground structures were introduced below the feedline to distinctly widen the stopband and increase the out-of-band rejection.

Circular Quarter-Mode SIW Antenna for WBAN Application

ABSTRACTIn this paper, a miniaturized Substrate Integrated Waveguide (SIW) antenna is designed for 5.8 GHz Wireless Body Area Network application. The proposed antenna is based on a quarter-mode concept, which is acquired by cutting a circular patch into four quarters along the perfect magnetic walls. Later on, by etching a tilted-rectangular slot on the top of a quarter-mode SIW cavity, two modes TM210 and TM020 get coupled and in results, an enhancement in bandwidth is achieved. The performance of the fabricated antenna has been validated on pork tissues. The measured impedance bandwidth and the radiation efficiency of the antenna are 400 MHz [5.52–5.92 GHz] and 88.5%, respectively. The evaluated value of specific absorption rate on pork tissues is 1 W/kg averaged over 1 g mass of tissue, with the input power of 250 mW. The simulation results and the measurement results examined on pork tissues agree well with each other.

A novel compact dual‐band filter based on quarter‐mode substrate integrated waveguide and complementary split‐ring resonator

ABSTRACTThis article proposes a novel miniaturized dual‐band filter, which is implemented by combining quarter‐mode substrate integrated waveguide (QMSIW) and complementary split‐ring resonator (CSRR). The resonator consists of a QMSIW cavity and CSRR structure, which can miniaturize SIW filter by increasing electrical length of the CSRR. With the combination of two second‐order QMSIW filters of different size, two propagating passbands can be generated. Based on the proposed structure, a dual‐band prototype is designed, fabricated, and measured. The measured passbands are centered at 3.5 GHz with about 3.3% bandwidth and 5.7 GHz with about 6.4% bandwidth. The measured minimum insertion loss for lower and upper bands is 0.98dB and 0.81dB respectively. While the insertion loss for all passbands is better than 2dB. The propose dual‐band filter has good performance in insertion loss with compact size, which has a great potential in the application of communication systems. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2704–2707, 2016