Showing papers on "Frequency band published in 2017"

Dual mode communications device and methods for use therewith

Abstract: In accordance with one or more embodiments, a communication device includes a dual-band antenna array configured to communicate RF signals in an RF band and to communicate MMW signals in a MMW frequency band with a remote device At least one transceiver is configured to generate the RF signals conveying a command to the remote device to transmit probe signals in the MMW frequency band, to receive the probe signals via the dual-band antenna in the MMW frequency band, and is initialized with first antenna beam steering parameters to facilitate a first antenna beam of the dual-band antenna array for the operation in the MMW frequency band A controller is configured to generate the first antenna beam steering parameters based on the probe signals and to generate the control signal to switch the dual-band antenna array to the operation in the MMW frequency band after transmission of the RF signals

On Indoor Millimeter Wave Massive MIMO Channels: Measurement and Simulation

Abstract: The millimeter wave (mmWave) communications and massive multiple-input multiple-output (MIMO) are both widely considered to be the candidate technologies for the fifth generation mobile communication system. It is thus a good idea to combine these two technologies to achieve a better performance for large capacity and high data-rate transmission. However, one of the fundamental challenges is the characterization of mmWave massive MIMO channel. Most of the previous investigations in mmWave channel only focus on single-input single-output links or MIMO links, whereas the research of massive MIMO channels mainly focus on a frequency band below 6 GHz. This paper investigates the channel behaviors of massive MIMO at a mmWave frequency band around 26 GHz. An indoor mmWave massive MIMO channel measurement campaign with 64 and 128 array elements is conducted, based on which, path loss, shadow fading, root-mean-square (RMS) delay spread, and coherence bandwidth are extracted. Then, by using our developed ray-tracing simulator calibrated by the measurement data, we make the extensive ray-tracing simulations with 1024 antenna elements in the same indoor scenario, and get insights into the variation tendency of mean delay and the RMS delay with different array elements. It is observed that the measurement and the ray-tracing-based simulation results have reached a good agreement.

Circularly-Polarized Reconfigurable Transmitarray in Ka-Band With Beam Scanning and Polarization Switching Capabilities

Abstract: The design, realization, and experimental characterization of a 400-element electronically reconfigurable transmitarray operating in the Ka-band is presented. It is based on linearly polarized unit-cells with 180° phase-shifting capability. Several sequential rotation schemes have been compared numerically to generate a circularly polarized beam over a broad frequency band, and a random distribution has been selected to mitigate spurious cross-polarized side-lobes when scanning the main beam. The 2-D electronic beam-steering capabilities of ±60° have been verified experimentally. The prototype, illuminated by a horn antenna as a focal source, exhibits a broadside gain of 20.8 dBi at 29.0 GHz and a 3-dB bandwidth of 14.6% with radiation efficiency of 58%. The axial ratio remains below 2 dB within this bandwidth. Next, a planar substrate integrated waveguide focal source array was designed in order to reduce the focal distance by about 50% and thereby significantly improve the antenna compactness, and similar radiation performance is demonstrated numerically and experimentally. © 1963-2012 IEEE.

Dual mode communications device with remote radio head and methods for use therewith

Abstract: In accordance with one or more embodiments, a communication device includes a dual-band antenna array configured to transmit first radio frequency (RF) signals to a remote device in an RF band and to transmit first millimeter wave (MMW) signals to the remote device in a MMW frequency band, wherein the MMW frequency band is above the RF band A base transceiver station is configured to generate a consolidated steering matrix in accordance with the transmission of the first RF signals to the remote device in the RF band A remote radio head is configured to convert the consolidated steering matrix to a converted steering matrix that facilitates the transmission of the first MMW signals to the remote device in the MMW frequency band, and further configured to generate the first MMW signals in accordance with the converted steering matrix

Dual mode communications device with null steering and methods for use therewith

Abstract: In accordance with one or more embodiments, a communication device includes a dual-band antenna array configured to transmit first radio frequency (RF) signals to a remote device in an RF band and to transmit first millimeter wave (MMW) signals to the remote device in a MMW frequency band, wherein the MMW frequency band is above the RF band. A base transceiver station is configured to generate a consolidated steering matrix in accordance with the transmission of the first RF signals to the remote device in the RF band. A remote radio head is configured to convert the consolidated steering matrix to a converted steering matrix that facilitates the transmission of the first MMW signals to the remote device in the MMW frequency band via the dual-band antenna array in accordance with an antenna beam pattern having at least one selected null direction, and further configured to generate the first MMW signals in accordance with the converted steering matrix.

Review of MEMS Electromagnetic Vibration Energy Harvester

Abstract: This paper mainly introduces the research progress of MEMS electromagnetic vibration energy harvester, hoping to provide valuable guidance and reference for researchers in related fields. In this paper, recent studies are divided into three groups according to their objectives and approaches: reducing the resonant frequency of the harvester to collect low frequency vibration energy from the environment; broadening the bandwidth of the harvester to increase the utilization of the random vibration energy; and developing new process compatible with MEMS for mass production. Besides, maintaining valuable output performances, such as power and power density, is also an important concern in these studies. Limited to the current technology, it is impossible to make a perfect harvester with low resonant frequency, wide frequency band, good compatibility with MEMS, and good output performances at the same time. However, we can focus on one or two characteristics according to the application, to which this paper provides valuable reference. More works on simulation, new process, and detailed design of the components are required in MEMS electromagnetic vibration energy harvesters.

Ultrawideband (UWB) Planar Antenna with Single-, Dual-, and Triple-Band Notched Characteristic Based on Electric Ring Resonator

Abstract: The ultrawideband (UWB) planar antenna is designed as a circular metallic patch fed by a coplanar waveguide (CPW). This antenna provides the impedance bandwidth of the wideband response from 2.5 to 12 GHz. To achieve the notched characteristics at desirable frequencies, the electric ring resonator (ERR) incorporated into the CPW feedline is proposed for use in the planar configuration of the UWB antenna. The notched frequency band is controlled by dimensions of the ERR structure. The single-notched band can be obtained by placing a single ERR beneath the CPW structure. For implementation of the multinotch band, a modified multimode structure of the ERR is examined. Reconfigurability of the first notched band is provided by using a digital variable capacitor (DVC) instead of ERR's quasi-lumped capacitance. The results of simulations and measurements are in a good agreement.

A New View of Multi-User Hybrid Massive MIMO: Non-Orthogonal Angle Division Multiple Access

Abstract: This paper presents a new view of multi-user (MU) hybrid massive multiple-input and multiple-output (MIMO) systems from array signal processing perspective. We first show that the instantaneous channel vectors corresponding to different users are asymptotically orthogonal if the angles of arrival of users are different. We then decompose the channel matrix into an angle domain basis matrix and a gain matrix. The former can be formulated by steering vectors and the latter has the same size as the number of RF chains, which perfectly matches the structure of hybrid precoding. A novel hybrid channel estimation is proposed by separately estimating the angle information and the gain matrix, which could significantly save the training overhead and substantially improve the channel estimation accuracy compared with the conventional beamspace approach. Moreover, with the aid of the angle domain matrix, the MU massive MIMO system can be viewed as a type of non-orthogonal angle division multiple access to simultaneously serve multiple users at the same frequency band. Finally, the performance of the proposed scheme is validated by computer simulation results.

Numerical study of an ultra-broadband near-perfect solar absorber in the visible and near-infrared region.

Abstract: We propose and numerically investigate a novel ultra-broadband solar absorber by applying iron in a 2D simple metamaterial structure. The proposed structure can achieve the perfect absorption above 95% covering the wavelength range from 400 to 1500 nm. The average absorption reaches 97.8% over this wavelength range. The broadband perfect absorption is caused by the excitation of localized surface plasmon resonance and propagating surface plasmon resonance. We first propose and demonstrate that the iron is obviously beneficial to achieve impedance matching between the metamaterial structure and the free space over an ultra-broad frequency band in the visible and near-infrared region, which play an extremely important role to generate an ultra-broadband perfect absorption. In order to further broaden the absorption band, we also demonstrate the perfect absorption exceeding 92% for the 400–2000 nm range by adding the number of metal-dielectric pairs and using both gold and iron simultaneously in the proposed structure. The average absorption of the improved absorber reaches 96.4% over the range of 400–2000 nm. The metamaterial absorbers using iron are very promising for many applications, which can greatly broaden the perfect absorption band in the solar spectrum and, meanwhile, can enormously reduce the cost in the actual production.

Wideband and High-Gain Corporate-Fed Gap Waveguide Slot Array Antenna With ETSI Class II Radiation Pattern in $V$ -Band

Abstract: We present a $V$ -band multilayer corporate-fed slot array antenna with wide impedance bandwidth and high efficiency. The proposed antenna consists of three unconnected metal layers based on the recently introduced gap waveguide technology. A $2\times 2$ cavity-backed slot subarray acts as the unit cell of the array. The top metal layer contains the radiating slots, the intermediate layer contains the cavities, formed by pins, and the third layer is the ridge gap waveguide corporate-feed network. The latter is realized by a texture of pins and guiding ridges to uniformly excite the cavities with the same amplitude and phase. The proposed antenna fulfills the radiation pattern requirement of the ETSI 320 standard. A prototype consisting of $16\times 16$ slots was manufactured by a fast modern planar 3-D machining method, i.e., die-sink electric discharge machining. The fabricated prototype has a relative impedance bandwidth of 17.6% with input reflection coefficient better than −10 dB. The E- and H-planes radiation patterns satisfy the ETSI class II copolar sidelobe envelope, and the measured cross-polar level is more than −30 dB below the copolar level over the 56–75 GHz frequency band. The measured antenna efficiency is better than 60% over the same band.

Calibration of the Advanced LIGO detectors for the discovery of the binary black-hole merger GW150914

Abstract: In Advanced LIGO, detection and astrophysical source parameter estimation of the binary black hole merger GW150914 requires a calibrated estimate of the gravitational-wave strain sensed by the detectors. Producing an estimate from each detector’s differential arm length control loop readout signals requires applying time domain filters, which are designed from a frequency domain model of the detector’s gravitational-wave response. The gravitational-wave response model is determined by the detector’s opto-mechanical response and the properties of its feedback control system. The measurements used to validate the model and characterize its uncertainty are derived primarily from a dedicated photon radiation pressure actuator, with cross-checks provided by optical and radio frequency references. We describe how the gravitational-wave readout signal is calibrated into equivalent gravitational-wave-induced strain and how the statistical uncertainties and systematic errors are assessed. Detector data collected over 38 calendar days, from September 12 to October 20, 2015, contain the event GW150914 and approximately 16 days of coincident data used to estimate the event false alarm probability. The calibration uncertainty is less than 10% in magnitude and 10° in phase across the relevant frequency band, 20 Hz to 1 kHz.

60-GHz Groove Gap Waveguide Based Wideband $H$ -Plane Power Dividers and Transitions: For Use in High-Gain Slot Array Antenna

Abstract: Wideband design of power dividers, T-junctions, and transitions based on groove gap waveguide (GGW) technology is presented in this paper with the goal to use these components in high-gain millimeter-wave antenna array design at 60-GHz frequency range. Since this GGW technology does not require electrical contact between the different metal layers of a complex 3-D waveguide structure, the fabrication cost and mechanical complexity are decreased. The designed T-junctions and different power dividers exhibit wide operational bandwidth and low output power and phase imbalance over the 60-GHz frequency band. Also, two transitions from GGW to a standard rectangular waveguide have been designed. To validate the performance of the designed components, a 64-way power divider in combination with 256 radiating slots is designed, prototyped, and measured at 60-GHz band. Measurement results agree well with the simulated performance of the complete array antenna, and the antenna gain is more than 32.5 dBi. The total radiation efficiency is more than 80% over the operating frequency range from 57 to 67 GHz. Also, the measured sidelobe levels are found to be agreeing well with the simulated level.

Broadband Amplification of Low-Terahertz Signals Using Axis-Encircling Electrons in a Helically Corrugated Interaction Region.

Abstract: Experimental results are presented of a broadband, high power, gyrotron traveling wave amplifier (gyro-TWA) operating in the (75-110)-GHz frequency band and based on a helically corrugated interaction region. The second harmonic cyclotron mode of a 55-keV, 1.5-A, axis-encircling electron beam is used to resonantly interact with a traveling TE_{21}-like eigenwave achieving broadband amplification. The gyro-TWA demonstrates a 3-dB gain bandwidth of at least 5.5 GHz in the experimental measurement with 9 GHz predicted for a wideband drive source with a measured unsaturated output power of 3.4 kW and gain of 36-38 dB. The approach may allow a gyro-TWA to operate at 1 THz.

All-sky search for periodic gravitational waves in the full S5 LIGO data

Abstract: We report on an all-sky search for periodic gravitational waves in the frequency band 20–475 Hz and with a frequency time derivative in the range of [−1.0,+0.1]×10−8 Hz/s. Such a signal could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our galaxy. This search uses the data from Advanced LIGO’s first observational run, O1. No periodic gravitational wave signals were observed, and upper limits were placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude h0 are ∼4×10−25 near 170 Hz. For a circularly polarized source (most favorable orientation), the smallest upper limits obtained are ∼1.5×10−25. These upper limits refer to all sky locations and the entire range of frequency derivative values. For a population-averaged ensemble of sky locations and stellar orientations, the lowest upper limits obtained for the strain amplitude are ∼2.5×10−25.

Harmonic Suppression and Stability Enhancement for Parallel Multiple Grid-Connected Inverters Based on Passive Inverter Output Impedance

Abstract: In this paper, the inverter output impedance is passivized for solving the harmonic and the stability problems in the multiparallel inverters The harmonics are easily aroused because of the disturbances, and the system stability is challenged by the grid impedance Based on the simplified equivalent impedance model, the two problems are analyzed in the low-frequency (LF) band and the high-frequency (HF) band, respectively Aiming at improving the LF performance, the weighted-proportional grid voltage feedforward and the harmonic quasi-resonant controller with phase compensation are proposed The dynamic performance is enhanced with an additional current reference generation scheme In order to improve the HF performance, a novel digital phase lead filter which brings the system back to a minimum-phase case is proposed By the proposed control method, the high modulus of each inverter output impedance $Z_{o}$ is guaranteed, while the phase angles of $Z_{o}$ over the entire frequency band are avoided to be lower than −90° The experiments based on four-parallel inverters have been conducted to validate the effectiveness of the proposed control method

Dual-Band Transmitarrays With Dual-Linear Polarization at Ka-Band

Abstract: Dual-band transmitarray antennas are demonstrated at Ka-band with the capability of forming independent linearly polarized beams with a given polarization in each frequency band, while sharing the same radiating aperture. The proposed three-layer unit-cell is based on identical narrow microstrip patches printed on both receiving and transmitting layers and connected by a metallized via hole. The metal layers are printed on two identical substrates bonded with a thin film, and the designed unit-cell exhibits a 180° phase resolution (i.e., 1-b phase quantization). The dual-band dual-polarized property of the transmitarray is achieved by interleaving unit-cells operating in the down-link and up-link frequency bands. Four different prototypes are characterized to demonstrate the relevance of the proposed concepts. A good agreement is obtained between the radiation patterns, gain curves, and cross-polarization levels measured and computed in both frequency bands and polarizations.

Mutual-Coupling Reduction Using Metasurface Corrugations for 28 GHz MIMO Applications

Abstract: An efficient method for improving the mutual coupling between two antipodal Fermi-based tapered slot antennas is presented. This is achieved by using metamaterial-based corrugations, acting as a metasurface shield, etched on edge side of the substrate. An array of split-ring resonator unit cells is incorporated into the design to suppress leakage from the side walls and to improve the isolation. The effect of metasurface corrugations results in a mutual coupling improvement of 12–15 dB over a frequency band from 27 to 32 GHz. Moreover, the radiation characteristic of the proposed antenna is not affected, leading to a higher gain and improved total efficiency with low mutual coupling. The proposed antenna is a suitable candidate for 28 GHz multiple-input–multiple-output (MIMO) systems. The measured isolation of the prototype antenna varies from −37.1 to −49.8 dB along with a measured gain of 16.13–17.92 dB over an operating frequency band from 27 to 32 GHz.

Octave and Decade Printed UWB Rectifiers Based on Nonuniform Transmission Lines for Energy Harvesting

Abstract: Ambient RF energy harvesting is a potential energy source for low-power and battery-less wireless sensors, enabling a range of applications from monitoring to security as part of the Internet-of-Things (IoT) scenario. One of the main challenges of ambient RF energy harvesting is the requirement of operation over a multitude of frequency bands of low ambient power densities resulting in a very wide aggregate operating bandwidth. In this paper, design examples of novel ultra-wideband energy harvesters are demonstrated with octave and decade bandwidths in the UHF and low microwave spectrum. The RF-dc conversion efficiency is maximized by tailoring the dimensions of a nonuniform transmission line used to provide broadband impedance matching. The design challenges in terms of impedance matching based on the Bode-Fano theoretical limit, losses and miniaturization are highlighted. Two prototypes are presented and their performance is evaluated. The octave band rectifier showed a measured RF-dc conversion efficiency of more than 60% over a frequency band of 470 to 860 MHz at 10-dBm input power. The decade band rectifier fabricated on Kapton substrate using inkjet printing featured a higher than 33% efficiency over a frequency band from 250 MHz to 3 GHz at 10-dBm input power.

A Broadband Circular Polarizer Based on Cross-Shaped Composite Frequency Selective Surfaces

Abstract: A cross-shaped composite with frequency selective surfaces is applied in the design of a broadband polarizer. The structure is multilayer, and the unit cell of each layer consists of a composite cross and a metal strip. The design takes advantage of both the similar amplitude and the stable phase difference of nearly 90° of the two orthogonal components of transmitted waves. The bandwidth of the polarizer reaches 74%, from 5.15 to 11.20 GHz, which is able to generate circular-polarization waves from incident linear waves. A sample polarizer is fabricated and tested. According to the measurement results, the polarizer operates from 5.75 to 11.20 GHz at normal incidence. In addition, its working frequency band can still cover the range of 5.80 to 11.00 GHz when the incident angle increases to 20°.

MIMO Antenna Using Hybrid Electric and Magnetic Coupling for Isolation Enhancement

Abstract: This paper presents a multiple-input and multiple-output antenna using a wideband decoupling structure for enhancing isolation. The decoupling structure is formed by a split ring, which consists of an inductive line and a capacitive gap to realize magnetic and electric coupling, respectively. By introducing the electric coupling in addition to the magnetic coupling, more degrees of freedom are obtained and the original coupling between antennas can be canceled out within a wide frequency band. Meanwhile, the performance of each antenna element is maintained, such as impedance bandwidth and radiation characteristics. Theoretical analysis and experimental verification are carried out. When the decoupling structure is placed between these two monopole antennas with edge-to-edge space of only 5 mm ( $0.04\lambda _{0}$ at 2.5 GHz), more than 20 dB isolation is realized over the bandwidth of 2.3–2.9 GHz (24%) with $S_{11}$ and $S_{22}$ less than −10 dB. Moreover, the isolation levels reach more than 30 dB over the frequency band of 2.3–2.8 GHz. Compared with the previous related works using decoupling networks and neutralization line techniques, the proposed decoupling structure can provide higher isolation of over 30 dB in a wider bandwidth.

Assessment of LTCC-Based Dielectric Flat Lens Antennas and Switched-Beam Arrays for Future 5G Millimeter-Wave Communication Systems

Abstract: This paper presents the design, low-temperature co-fired ceramics (LTCC) fabrication, and full experimental verification of novel dielectric flat lens antennas for future high data rate 5G wireless communication systems in the 60 GHz band. We introduce and practically completely evaluate and compare the performance of three different inhomogeneous gradient-index dielectric lenses with the effective parameters circularly and cylindrically distributed. These lenses, despite their planar profile antenna configuration, allow full 2-D beam scanning of high-gain radiation beams. A time-domain spectroscopy system is used to practically evaluate the permittivity profile achieved with the LTCC manufacturing process, obtaining very good results to confirm the viability of fabricating inhomogeneous flat lenses in a mass production technology. Then, the lenses performance is evaluated in terms of radiation pattern parameters, maximum gain, beam scanning, bandwidth performance, efficiencies, and impedance matching in the whole frequency band of interest. Finally, the performance of the three lenses is also experimentally evaluated and compared to a single omni-directional antenna and to a ten-element uniform linear array of omni-directional antennas in real 60 GHz wireless personal area network indoor line-of-sight (LOS) and obstructed-LOS environments, obtaining interesting and promising remarkable results in terms of measured received power and root-mean-square delay spread. At the end of this paper, an innovative switched-beam antenna array concept based on the presented cylindrically distributed effective parameters lens is also introduced and completely evaluated, confirming the potential applicability of the proposed antenna solution for future 5G wireless millimeter-wave communication system.

Wideband frequency reconfigurable Koch snowflake fractal antenna

Abstract: In this study, a Koch snowflake frequency reconfigurable antenna for wideband applications is presented including experimental verification. The frequency reconfigurable approach is obtained for UHF band using RF PIN diodes, lumped capacitor and inductors. Proposed antenna is compact, therefore, it can be used as an array element. It has three measured frequency bands. These bands are: case I, 3.34- 4.52 GHz (30%); case II, 2.2-3.4 GHz (43%); and case III, 1.45-4.1 GHz (95.49%). In cases I and II, two different bands are obtained and case III covers almost the frequency band of case I and case II. Thus, the impedance bandwidth of the proposed antenna provides continuous wideband frequency coverage from 1.45 to 4.52 GHz (103%). In addition, the measurements are carried out to validate the performance of the antenna. The proposed antenna has good agreement between simulated and measured results with reasonably low cross polarisation.

Low-frequency noise attenuation in seismic and microseismic data using mathematical morphological filtering

Abstract: Low-frequency noise is one of the most common types of noise in seismic and microseismic data. Conventional approaches, such as the high-pass filtering method, utilize the low-frequency nature and distinguish between signal and noise based on their different frequency contents. However, conventional approaches are limited or even invalid when the signal and noise shares the same frequency band. Moreover, high-pass filtering method will suppress not only low-frequency noise but also low-frequency signal when they overlap in a same frequency band, which is extremely important in the inversion process for building the subsurface velocity model. To overcome the drawbacks of conventional high-pass filtering approach, we developed a novel method based on the mathematical morphology theorem to separate signal and noise using their differences in morphological scale. We extracted empirical relation between morphological scale and frequency band so that the mathematical morphology based approach can be conveniently used in low-frequency noise attenuation. The proposed method is termed as the mathematical morphological filtering (MMF) method. We compare the MMF approach with high-pass filtering and empirical mode decomposition (EMD) approaches using synthetic, reflection seismic and microseismic examples. The various examples demonstrate that the proposed MMF method can preserve more low-frequency signal than the high-pass filtering approach, and is more efficient and causes fewer artefacts than the EMD approach.

An FSS-Based Nonplanar Quad-Element UWB-MIMO Antenna System

Abstract: In this letter, a low-profile, miniaturized four-element ultrawideband (UWB) antenna for four-port multiple-input–multiple-output (MIMO) configuration is proposed. The MIMO antenna elements are organized in a cuboidal geometry around a polystyrene block. An inverted L-shaped structure provides decoupling among the antenna elements. This structure is frequency-selective-surface-based and has slotted Y-shapes etched in it. In addition to that, a square spiral parasitic structure improves input impedance matching over the desired frequency band. Antenna elements are realized on low-profile FR-4 substrate having compact dimensions of 32 × 36 × 1.5 mm $^{3}$ . The proposed three-dimensional (3-D) UWB-MIMO system achieves good impedance matching and an effective isolation of 20 dB among antenna elements in most of the band. The reported configuration is suitable for nonplanar/3-D system-in-package applications where a planar arrangement of four elements is not possible due to size limitations.

Mechanical low-frequency filter via modes separation in 3D periodic structures

Abstract: This work presents a strategy to design three-dimensional elastic periodic structures endowed with complete bandgaps, the first of which is ultra-wide, where the top limits of the first two bandgaps are overstepped in terms of wave transmission in the finite structure. Thus, subsequent bandgaps are merged, approaching the behaviour of a three-dimensional low-pass mechanical filter. This result relies on a proper organization of the modal characteristics, and it is validated by performing numerical and analytical calculations over the unit cell. A prototype of the analysed layout, made of Nylon by means of additive manufacturing, is experimentally tested to assess the transmission spectrum of the finite structure, obtaining good agreement with numerical predictions. The presented strategy paves the way for the development of a class of periodic structures to be used in robust and reliable wave attenuation over a wide frequency band.

Broadband Printed-Circuit-Board Characterization Using Multimode Substrate-Integrated- Waveguide Resonator

Abstract: Broadband printed-circuit-board characterization using a multimode substrate-integrated-waveguide (SIW) resonator is proposed and investigated in this paper. The resonator sample is fed by two closed rectangular waveguides through two coupling slots positioned at two ends of the cavity. A series of TE $_{\mathrm {10}{k}}$ resonant modes with large mode index can be excited sequentially in the cavity. This design is able to perform an effective control of the frequency interval ( $\Delta f$ ) between two neighboring modes. Besides, $\Delta f$ approaches to be a constant with a large mode index $k$ . This feature is important to test dielectric materials at small and approximately uniform frequency intervals. The detailed design process is introduced to synthesize the dimensions of the resonator sample and the feeding structure for a given operation frequency band. As an example, the Taconic TLY-5 substrate is measured at $Ka$ -band firstly to validate the accuracy of this method. Two types of samples with different thicknesses are fabricated and tested to calibrate the conductor loss. After that, this SIW multimode measurement is employed to accurately test the same substrates over the whole $W$ -band with approximately uniform frequency intervals. This task cannot be implemented by conventional resonance methods based on microstrip lines because of the selection of resonant modes and the radiation leakage.