Substrate Integrated Waveguide Power Research Articles

A stable high-gain cavity-stacked antenna array with compact high-order mode fed for W-band applications

This paper presents a W-band stable high gain 2 × 2 cavity-backed slot antenna array fed by compact high-order mode substrate-integrated cavity (SIC) with substrate-integrated waveguide (SIW) technology. The antenna element incorporates a 2 × 2 subarray of cross-shaped slots, excited by a high-order mode (TE220) SIC, ensuring uniform amplitude and balanced phase to achieve stable high-gain and high efficiency. Moreover, an additional SIW cavity is stacked above the 2 × 2 cross-shaped slots, incorporating a rectangular slot etched on the surface of the SIW cavity for radiation to further enhance the gain. This novel architecture yields a gain enhancement of 2.6 dBi compared to the traditional unstacked SIW cavity antenna. A prototype antenna array, consisting of 2 × 2 radiation elements and a low-loss 1-to-4 SIW power divider integrated with waveguide (WG) to SIW transition, is designed and fabricated in standard PCB technology. The measured results exhibit a −10 dB impedance bandwidth range from 91 to 97 GHz, a peak gain of 18.5 dBi, and a peak aperture efficiency of up to 78 %.

The Art of Substrate-Integrated-Waveguide Power Dividers

Substrate-integrated-waveguide (SIW) technology can eliminate the limitations associated with conventional rectangular waveguides, i.e., bulky structures and production complexity at higher frequencies. Moreover, SIW technology replaces microstrip structures eliminating the drawback of excessive radiation leakage at higher frequencies. SIW power dividers are key elements in SIW antenna array synthesis. A SIW power divider’s design procedures are more complicated than conventional microstrip power dividers. However, no comprehensive review with design guidelines of substrate-integrated-waveguide (SIW) power dividers has been reported. In this paper, different types of SIW power dividers based on their configurations, functionality, and operating principles are analyzed and some recommendations are made for selection purposes. A comprehensive design guideline for SIW power dividers is given in this paper through a comparative study of T- and Y-type SIW junctions. These guidelines are based on key parameters, including insertion loss, isolation, co-phase bandwidth, return loss bandwidth, and phase balancing. This study provides valuable information for selecting and designing the best possible configuration of SIW power dividers for specific applications in microwave and millimeter-wave frequency ranges. A case study of a Ku-band SIW power divider is performed for a Ku-band soil moisture radiometer SIW antenna array.

A D-Band Magnetoelectric Dipole Antenna-in-Package (AiP) Implemented on BT-Based Organic Substrate

A high gain, wide bandwidth (BW), and low-profile <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> -band magnetoelectric dipole antenna-in-package (AiP) is proposed in this article. The unit antenna with a cavity backed slot is first evaluated by a substrate integrated waveguide (SIW) feed structure. The simulated impedance BW of the unit antenna covers 27 GHz from 132 to 159 GHz with stable broadside radiation patterns. Then, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times $ </tex-math></inline-formula> 2 array based on the proposed unit antenna is designed and verified on a four layer BT-based organic substrate. The array design is composed of an isolation, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> 2 subarray, a two-way SIW power divider, and a probe pad to SIW transition. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> 2 subarray is realized by a four-way broad wall coupler with a V-junction design in particular. Tested by probing on substrate in the direct far-field chamber, the measured impedance BW covers 23.4 GHz from 135.4 to 158.8 GHz with a peak gain of 14.1 dBi at 150 GHz. The average of measured gains within the 130–160-GHz band is 12 dBi. Modeled with the dimensions of structural analysis results from optical microscope (OM) and cross-sectional scanning electron microscope (SEM) inspection, the post-simulation result shows a good agreement with the measurement result, including impedance BW, radiation patterns, and gains. This article demonstrates that the proposed AiP using the low-cost BT-based substrate manufacturing technology can be a good candidate for the future <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> -band applications.

The chamfered bend two, four and eight-way SIW power dividers analysis for millimeter wave applications using the quick finite element method

In this paper, we propose three kinds of substrate-integrated waveguide (SIWs) based chamfered bend power divider junctions provide equal power distribution to all output ports while maintaining high isolation and operating in the 54 GHz to 60 GHz frequency band. The advantages of the SIW technology are ease of design, fabrication and low form and full integration with planar printed circuits. In this case, the concept of the SIW H-plane power divider is implemented using a rigorous two-dimensional quick finite element method (2D-QFEM) programmed by MATLAB software. The numerical performance of this method is the Quick simulation time for using the mesh with Delaunay regularization in two dimensions, if we increase the mesh the FEM gives better results. This paper presents the transmission coefficient, return loss and the electric field distribution. The results obtained from QFEM were compared with those provided by HFSS for validation. When using the discretization with the Delaunay procedure only in two dimensions, we notice that the calculated simulation time decreases with good precision.

A Compact and Broadband Balun Based on Multilayer SIW

A compact broadband balun based on a new planar wideband power divider circuit is presented in this work, which makes use of the substrate integrated waveguide (SIW) technique and multilayer printed circuit board (PCB) process. A broadband 180° reverse-phase characteristic between the two output ports can be easily achieved by the middle metal-ground of the SIW power divider. An elliptic coupling slot is utilized for this multilayer SIW power divider to realize a broad passband. The concept is validated by simulation and measurement. The measured results suggest that a 10 dB return loss at the input can easily be achieved, across a 50.3% relative bandwidth from 11.3 to 18.9 GHz. The measured amplitude and 180° phase imbalance between the two outputs are within 0.35 dB and 1.9°, respectively.

Leaky-Wave Antenna Array With Bilateral Beamforming Radiation Pattern and Capability of Flexible Beam Switching

A novel leaky-wave antenna (LWA) array capable of bilateral beamforming is investigated for applications in indoor and short-distance mobile communications. The antenna array is designed on a double-layer substrate-integrated waveguide (SIW) with a multiport feeding network. The upper layer is a four-port SIW with a tapered open stopband suppression structure and two tapered radiating slot arrays. By adjusting the periods and widths of slots, the two slot arrays radiate in different directions, and their radiation fields satisfy the cosecant-squared distribution. The lower layer is a single-port SIW power divider with an allocation ratio of 1:5 using a Z-shaped junction. There are transitions at both ends of the lower SIW for coupling energy up into the radiation layer. When feeding the upper layer from its two input ports individually, two dual broad beams with beam directions of ±25° and ±45° can be generated, thus achieving amplitude-shaped dual-beam switching for smart beam switching antenna systems applied in short-distance mobile communication. When feeding the whole double-layer array through the input port of the power divider, the above two dual beams will be superposed together and form a cosecant-squared radiation pattern, which is suitable for uniform radio wave coverage along with straight areas. The proposed array was fabricated and measured to validate its performance, and the results showed the efficiency of the design.

Design and implementation of compact tri- and quad-band SIW power divider using modified circular complementary split-ring resonators

AbstractThis paper presents a miniaturized tri- and quad-band power divider (PD)based on substrate integrated waveguide (SIW). By adopting different types of modified circular complementary split-ring resonators on the top surface of SIW, multiple passbands are generated propagating below the SIW cut-off frequency. The working principle is based on evanescent mode propagation that decreases the operating frequency of the PD and helps in the miniaturization of the proposed structure. The operating frequency of the proposed PD can be individually controlled by changing the dimensions of the resonator. To verify the proposed concept, a tri-band and a quad-band PD exhibiting 3 dB equal power division at 2.41/3.46/4.65 GHz and 2.42/3.78/4.74/5.8 GHz are designed using the full-wave simulator, validated through circuit model, fabricated and experimentally verified. The measured results agree well with the simulations. The proposed PDs have good performance in terms of reasonable insertion loss, isolation, minimum amplitude and phase imbalance, smaller footprint, easy fabrication and integration. The size of the fabricated prototype is 18.3 mm × 8.4 mm, which corresponds to 0.205λg × 0.094λg, λg being the guided wavelength at the first operating frequency.

Wideband aperture coupled substrate integrated waveguide power divider based on half mode analysis

A wideband substrate integrated waveguide (SIW) power divider based on half mode analysis is presented in this article. The structure is constructed by two substrate layers and three metal layers. Two symmetrical longitudinal apertures etched on the middle ground are introduced to realize the equal power division, and couple the signal from the SIW to the upper layer output ports simultaneously. Two fork-type microstrip lines on the top metal layer are used to improve the bandwidth of the power divider. The equivalent circuit based on the half mode analysis method is presented for theoretical analysis and further design of the power divider, and good impedance matching can be obtained accordingly. For demonstration, a power divider prototype with the dimension of 48 × 73 × 1.38 mm3 is designed, fabricated, and measured. Good agreement is observed between the simulated and measured results. The measured return loss of the SIW power divider is better than 12 dB in the frequency range of 6.2 ~ 10.3 GHz, and the insertion loss is around 1.6 dB over the entire frequencies of interest.

Compact Omnidirectional Millimeter-Wave Antenna Array Fed in Series by a Novel Feed Network

In this article, a novel substrate integrated waveguide power divider is proposed to feed antenna array elements in series. This feed network inherently provides uniform output power to eight quadrupole antennas. More importantly, it leads to a compact configuration since the feed network can be integrated inside the elements without increasing the array size. Its design procedure is first discussed. Next, the series feed network was used to feed a novel compact omnidirectional antenna array. Targeting the fifth-generation (5G) 26 GHz millimeter-wave (mm-wave) band, the simulated results showed that the proposed array exhibits a broad impedance bandwidth of 4.15 GHz and a high gain of 13.6 dBi. A prototype was fabricated and measured, exhibiting a measured impedance bandwidth of 6.72 GHz and a gain of 12.3 dBi. Its attractive features indicate that the proposed antenna array is well suitable for millimeter-wave wireless communication systems.

Quasi‐Yagi antenna with parasitic cells and its array for 5G mm‐wave operations

AbstractA quasi‐Yagi antenna with parasitic cells and its array are proposed for 5G mm‐wave bands. For the antenna unit, through introducing the parasitic cells, the gain could be enhanced maximum of 1.3 dB without increasing the antenna length and a wide bandwidth served for the 5G N258 band. Besides, substrate integrated waveguide (SIW) with short‐circuit metal vias is employed as the feed structure and reflector, which can easily tune the impedance matching. For the antenna array, by designing a SIW power divider, the antenna element can be convenient to integrate as a 1 × 4 end‐fire array. The antenna unit and its array have been fabricated and measured. The measured results show that the high peak gain of the element and array is 9.06 and 14.38 dB within the operation bands (24.25–27.5 GHz), respectively. It is suitable for miniaturized end‐fire devices with 5G N258 mm‐wave operation systems.

A compact, broadband three-way substrate integrated waveguide power divider with improved isolation

PurposeThis paper aims to present a compact, broadband substrate integrated waveguide (SIW) three-way power divider with improved isolation based on six-port SIW coupler.Design/methodology/approachThe power coupling among the three output ports occurs due to short openings in the narrow walls of the central SIW channel. Performance improvement in the isolation and return loss among ports is achieved using matching posts placed at the input and output ends of the coupling region. This enhances the coupling between TE10 and TE30 modes. The input matching ports enhance the return loss, whereas the isolation is alleviated by both the input and output matching posts. The bandwidth enhancement is achieved by optimizing the outer SIW channel widths.FindingsThe measured fractional bandwidth of 27.3% with over 15 dB of isolation and return loss is achieved. The coupling length is 1.55 λg at the centre frequency. The power divider achieves better than 15 dB isolation between non-adjacent output ports. The measured reflection and isolation coefficients are in close agreement with simulated results over 8.2 to 10.8 GHz.Practical implicationsIsolation between the adjacent and non-adjacent ports is an important parameter as the reflections from these ports will interfere with signals from other ports reducing the fractional bandwidth of the power divider and affecting the overall performance of the transmitters and receivers.Originality/valueThe authors present the enhancement of isolation between the output non-adjacent ports by optimizing the SIW channel width and matching post in the coupling region to reduce the reflected signals from non-adjacent ports entering into other ports. To the author’s knowledge, this is the only SIW three-way power divider paper showing non-adjacent port isolation among six-port couplers based three-way power dividers.

Wideband split-ring antenna arrays based on substrate integrated waveguide for Ka-band applications

AbstractThis paper presents wideband split-ring antenna arrays based on substrate integrated waveguide (SIW) for Ka-band (26.5–40 GHz) applications. The antenna array is fed by a 2.92 mm coaxial connector (K-connector) and the power is equally distributed to each split-ring resonator. The designed coplanar waveguide (CPW), SIW, CPW-to-SIW transition, coaxial-to-CPW transition, and two-stage SIW power divider are described in detail. By using a thin Rogers 6002 substrate with silver epoxy-filled vias, a transition prototype is designed, fabricated, and tested in a back-to-back configuration. A wideband split-ring resonator is developed as a single element and four possible arrangements of antenna arrays are introduced. By combining the designed components and routing paths, two full layouts of the antenna arrays with four split-ring resonators are addressed. As a demonstrator, a 2×2 antenna array prototype in a compact format is designed, fabricated, and tested. The fabricated antenna array achieves a measured directivity of 15.0 dBi with a fractional bandwidth of 23.0% centered at 30.5 GHz.

Wideband Rectangular Waveguide to Substrate Integrated Waveguide (SIW) E-Plane T-Junction

A broadband rectangular waveguide to substrate integrated waveguide power divider for hybrid beam forming networks is presented. Rectangular waveguide symmetric E-plane irises are used to realize a multi-section matching network. A hybrid circuit and full-wave design procedure are described and adopted to synthesize three matching networks with one, two, and three irises, progressively increasing the bandwidth and exceeding the state of the art in the last two cases. Three proof-of-concept prototypes are manufactured and tested to validate the design procedure. Good agreement between simulated and measured performance confirms the validity of the proposed solution.

A compact high-performance patch array with suppressed cross polarization using image feed configuration

In this paper, first, a 2 × 2 patch antenna array based on the substrate integrated-waveguide (SIW) with high efficiency, broadband, and low cross-polarization for X-band applications, is presented. Simulation results indicate that the cross-polarization levels for the whole bandwidth within the main beam half-power beamwidth (HBPW) are less than −30 dB. A 2 × 2 array is used as a basic radiating element to design and fabricate a 4 × 4 array. A SIW power distribution network is adopted for the 4 × 4 array design, whose operation is based on the change of the propagation emission mode. The feeding network implements the image feed technique. Measurement results show that the impedance bandwidth of the structure for S11 < −10 dB is about 12.9% from 9.4 to 10.7 GHz. The measured peak gain is 16.3 dBi at 10 GHz, which is equivalent to 66% aperture efficiency. The measured cross-polarization level over the whole bandwidth within the HBPW is less than −40 dB. The proposed array is the right candidate for X-band applications due to its advantages, such as compact size, wideband, high efficiency, and low cross-polarization.

A novel substrate integrated waveguide cavity‐backed self‐diplexing antenna array with frequency beam scanning characteristic

This article presented a substrate integrated waveguide (SIW) cavity-backed self-diplexing antenna array with frequency beam scanning characteristic. The proposed array consists of 16 SIW cavity-backed slot antennas. The SIW cavity-backed slot antenna can be fed by two separate ports to resonate at two different frequencies and achieve high isolation better than 20 dB between two input ports. The proposed element is a typical self-diplexing antenna. These cavity-backed slot antennas are shunt-fed by a compact 1 to 16 SIW power divider and series-fed by a set of microstrip lines, respectively. As a result, this array achieves an unidirectional radiation pattern at 10.2 GHz with high gain of 15.10 dBi, and a frequency beam scanning characteristic from 7.0 to 9.0 GHz ranging from −50° to 46°.

Broadband Eight-Way Substrate Integrated Waveguide Radial Power Divider/Combiner With High-Isolation

A broadband eight-way substrate integrated waveguide (SIW) radial power divider/combiner with high-isolation is presented. The step probes are utilized to achieve broadband impedance matching and improve the return loss. What's more, the star structure based on microstrip circuit is employed to improve the isolation performance. A two-layer SIW radial power divider/combiner is designed, fabricated and measured. Good agreement between simulated and measured results is achieved for the proposed power divider/combiner. The measured results show that both bandwidths of the input and output port are 25% and 20% when their return loss are lower than -15 dB. The measured output isolation is greater than 17.5 dB from 5.75 GHz to 7.85 GHz and greater than 20 dB from 6.8 GHz to 7.9 GHz. The presented eight-way SIW power divider/combiner has the advantage of wider bandwidth, lower return loss and insertion loss, and higher isolation between the outputs.

SIW Corporate-Feed Network for Circular Polarization Slot Array Antenna

In this paper, multilayer feeding network for linear slot array antenna is studied. A substrate integrated waveguide (SIW) corporate-feed network for linear slot array antenna based on three layers is presented. This design has eight right-handed circularly polarized radiation elements, one power divider with SMA connector to SIW adapter structure and six SIW power divider by coupling slot method. The feed network and antenna structures has been designed at X-band frequency. The SMA to SIW power divider and SIW power divider by coupling slot has in-phase and out-of-phase feature, respectively. The proposed feeding method takes the advantages of miniaturization of structure compared with the corporate-feed network by T-junctions. Also, proposed network for feeding radiation elements, eliminated undesirable surface current of the coaxial connector transition, which reduction of these currents causes lower side-lobe level at the antenna radiation pattern. Dimensions of manufacture array structure are 132.8 * 23 * 2.4 mm3 and the substrate is Rogers RO4003c. This antenna has the capability to expand the number of elements and feed network for achieving higher gain. Due to the unidirectional radiation pattern, this antenna useful for monopulse radar and automotive radar applications.

Wideband high‐gain SIW‐fed antenna array for mm‐Wave applications

AbstractA wideband high‐gain mm‐Wave antenna array operating in Ka‐band is reported. The antenna element consists of an antipodal Vivaldi antenna (AVA) with plated through vias on the edges of the radiating arms, which is utilized to eliminate the harmful gap resonance due to the electrically discontinuity. A modified wideband 8‐way substrate integrated waveguide (SIW) power divider is proposed to feed the linear array. In addition, in order to enhance antenna gain, a stacked dielectric superstrate is employed, which achieves 2.3 dBi average gain improvement over 25‐40 GHz. The proposed structure provides superior bandwidth of 25.4‐40 GHz with S11 &lt; −9.5 dB (corresponding to VSWR &lt; 2). The modified SIW power divider, 1 × 8 AVA array and the dielectric superstrate are designed and fabricated, resulting in a wideband and high‐gain structure as compared to other SIW‐fed antennas. A prototype is experimentally verified. The measured results show that the impedance bandwidth ranges from 25.37 to 39.48 GHz (S11 &lt; −9.6 dB, relative bandwidth of 43%). The measured gain varies from 15.5 to 18.5 dBi in the frequency range with an average gain of 16.6 dBi.

New miniaturized Wilkinson Power Divider based on a new Half Mode Substrate Integrated Waveguide and CRLH-TL

Objectives: In this study, two new power splitters integrated with a novel half mode substrate integrated waveguide (HMSIW) and composite right/left-handed transmission lines (CRLH-TL) cells are presented, realized and compared to a conventional Substrate Integrated Waveguide (SIW) one. Methods: The SIW technology is characterized by a high Q factor and a low return loss, but it suffers from the massive size particularly in low frequencies bands, so to achieve practically 50% miniaturization in size with keeping the high performances of the SIW technique, HMSIW origins from SIW has been utilized. otherwise, so as to reduce the HMSIW device, size, Composite Right/Left-Handed Transmission Lines (CRLH-TL) cells are applied. The designs are printed on a Roger RT/duroid 6010 and performed within an HFSS environment based on the finite element method (FEM). Simulations and measurements of the three power dividers are presented over a frequency band from 2.2 GHz to 2.6 GHz. Findings: The novel proposed component achieves about 70% and 90% of size reduction compared to, respectively, the HMSIW and SIW power splitters. The simulated and measured results are in close agreement. Application: Compared to the SIW power divider and the HMSIW one the novel proposed device is characterized by a compact size and an easy fabrication process. So that it will enable a convenient reduction of size, loss and cost in millimeter-wave and microwave systems.Keywords: Power Divider, HMSIW, SIW, CRLH-TL Cells, Tapered Transition

An SIW Horn Antenna Fed by a Coupled Mode Emulating Pyramidal Horn Antennas

A novel feeding method to dielectric loaded substrate-integrated waveguide (SIW) horn antennas is presented, resulting in equal half power beamwidths (HPBWs) and low sidelobe levels (SLLs) in both the E-plane and H-plane. The concept is to synthesize a unique electromagnetic field distribution using four vertically stacked SIWs. In particular, a uniquely adjusted excitation of magnitudes and phases of the four SIWs is employed as the feeding of the SIW horn, emulating the field distribution of pyramidal horn antennas. This approach realizes the phase correction of the electric field at the horn aperture and concentrates the radiation to the endfire direction to reduce the sidelobes. To prove the concept, a stacked dielectric loaded SIW horn antenna fed by four TE10 excitations was simulated at 35 GHz, yielding a gain of 15 dBi, an HPBW of 33° for both the E-plane and H-plane, and an SLL of approximately -24 dB for both the E-plane and H-plane. To achieve the desired excitation at each port, a narrowband SIW power splitter was designed to adapt a 3.5 mm coaxial connector to the four waveguide ports with the required phase shift. The entire feeding and antenna structure were fully substrate integrated and fabricated on Rogers 5880 panels. The measured radiation patterns show good agreement with the simulation with the best performance at 35.1 GHz.