Phase Deviation Research Articles

Multi-frequency coherent perfect absorption in the one-dimensional magnetized ferrite photonic structure

A controllable multi-frequency absorption structure predicated on a one-dimensional magnetized ferrite photonic crystals (MFPCs) that achieves coherent perfect absorption is designed and further analyzed by utilizing the transfer matrix method. By introducing the filter structures to the MFPC and using the gradient descent optimization algorithms to optimize its layer parameters, the multi-frequency coherent absorption curve is obtained. The suggested MFPC brings out about six absorption peaks whose absorptance can be higher than 0.99 at the same time under the transverse electric mode. Moreover, the absorptance can be regulated from 0.99 to less than 0.1 by merely changing the phase deviation between the two incident waves to the front and rear surfaces. Besides, the studied results demonstrate that the intensity of coherent absorption and the position of absorption peaks can be adapted by altering the magnetic field and the thicknesses of ferrite layers. It follows that the absorption peaks can cover most frequency points from 58.6 to 65.9 THz via changing the thicknesses of the external magnetic field and ferrite layers. Moreover, the structure also has the potential for wide-angle absorption. This research furnishes a significant reference for the design of the multi-frequency absorption optoelectronic device and phase sensor.

Millimeter‐wave metasurface lens aided phaseless characterization for quiet zone of compact antenna test range

AbstractThe quiet zone of compact antenna test range (CATR) is typically required as uniform as possible with a low phase deviation error. Here, we propose a novel phaseless CATR characterization method by combining a single millimeter‐wave metasurface lens‐based technique and an alternating projection algorithm. The metasurface lens provides two sets of weakly correlated amplitude‐only data to the algorithm by changing the propagation path of the pseudo‐plane wave, hence realizing the phase retrieval of the quiet zone with low complexity of measures. In addition, initial phase preprocessing is adopted to further improve the precision of phase retrieval. Furthermore, different alternating projection algorithms are compared to validate the effectiveness of the proposed method, showing the maximum phase error in the effective quiet zone reaches 0.75° at 220 GHz. In the end, the simulation results show that the proposed method can be applied in the ultra‐broadband frequency range of 120 GHz. In a nutshell, this paper provides new insights for the applications of metasurface lens in the phaseless characterization of CATR.

Method of Detecting Radio Signals using Means of Covert by Obtaining Information on the basis of Random Signals Model

The article presents a developed method for determining random radio signals. Random signals can be signals from hidden means of obtaining information.The signal is considered as a random process. The description of such signals is based on probability theory and the theory of random functions. In the practice of analysis of random radio signals, static methods based on the theory of stationary random functions have become widespread. The existing models of a stationary random process are not adequate for a large number of random processes, especially for processes that are dynamic in nature and are observed during a finite time interval.The developed method allows to detect signals from hidden means of obtaining information with greater efficiency. The novelty of the method is to determine the deviation of the main parameters of the signals from the function of the sample. The method is based on determining the function of a sample of signals of a given radio range. The function of the sample is obtained as the implementation of the smoothing function of a random process, by the method of least squares using the principle of sliding smoothing.It is proposed to determine the signals of the means of covert receipt of information by the instantaneous deviation of the parameters of random signals. To determine the signals of the means of covert obtaining information, it is proposed to determine the deviation of the amplitude of the random signals from the amplitude of the signals of the sample function, then, if necessary, to determine the deviation of the signal phases. So, the effectiveness of the method is achieved by determining two parameters of the deviation of the amplitude and phase. This makes it possible to detect random signals with a higher probability.Determining the function of the sample of the required radio band significantly increases the probability of determining random signals, by reducing the scanning time of a given radio band, by excluding known signals from the additional software analysis of a given radio band.

The relationship between stability of interpersonal coordination and inter-brain EEG synchronization during anti-phase tapping

Inter-brain synchronization is enhanced when individuals perform rhythmic interpersonal coordination tasks, such as playing instruments in music ensembles. Experimentally, synchronization has been shown to correlate with the performance of joint tapping tasks. However, it is unclear whether inter-brain synchronization is related to the stability of interpersonal coordination represented as the standard deviation of relative phase (SDRP). In this study, we simultaneously recorded electroencephalograms of two paired individuals during anti-phase tapping in three interactive tapping conditions: slow (reference inter-tap interval [ITI]: 0.5 s), fast (reference ITI: 0.25 s), and free (preferred ITI), and pseudo tapping where each participant tapped according to the metronome sounds without interaction. We calculated the inter-brain synchronization between pairs of six regions of interest (ROI): frontal, central, left/right temporal, parietal, and occipital regions. During the fast tapping, the inter-brain synchronization significantly increased in multiple ROI pairs including temporoparietal junction in comparison to pseudo tapping. Synchronization between the central and left-temporal regions was positively correlated with SDRP in the theta in the fast condition. These results demonstrate that inter-brain synchronization occurs when task requirements are high and increases with the instability of the coordination.

Optical analogue of the Thomas effect in special relativity using Michelson-Gires-Tournois interferometer: Comprehensive error analysis and recovery of the direction of the Thomas rotation angle

Previously, we reported a simple, low-cost, thin–film–based optical analogue of the Thomas Effect in Special Relativity (SR) using an ideal Michelson-Gires-Tournois interferometer (MGTI). This opens the door for other SR related phenomena to be studied analogously. Toward this goal, there are two important tasks. First, it is imperative to conduct a comprehensive evaluation of the technical limitations of this platform under two non-ideal (oftentimes unavoidable) operating conditions, namely: (i) an imperfect Gires-Tournois resonator (GTR), and (ii) the presence of interferometric error due to mismatch in the path-length arm difference of the MGTI. Second, it is also important to develop a technique to recover the direction information of the Thomas angle which is lost during the intensity measurement. Here, we report that (i) the GTR's imperfect back mirror must be fabricated with a minimum reflectance r0 value of greater than 0.9534 to limit the maximum phase deviation error by only less than 1%, (ii) the extracted Thomas angle is more sensitive to changes in interferometric error δl than the GTR imperfection. However, perfect extraction of the Thomas angle can be achieved for special range of the interferometric error δl, and (iii) the mimicked Thomas angle is distorted when the front reflectance coefficient r1 is greater than 0.7. Lastly, we introduce a method to recover the directional information of the Thomas angle by using a counter-intuitive additional positive/negative interferometric error. This method introduces no new optical components, and has high tolerance to fluctuation of the interferometric error.

A phase‐shifterless experimental scheme for power combination of two magnetrons utilizing a single RF power amplifier

AbstractVarious coherent power combining schemes have been developed with high power magnetrons to meet the increasing industrial demands of HPM and Wireless Power Transfer applications.In this paper, we propose a power combining scheme for two 1.25 kW magnetrons, based on phase‐shifter less philosophy. The proposed scheme utilizes a single signal generator synthesizing the injection signal for both magnetrons. A single RF Power Amplifier (PA) amplifies the injection signal for both magnetrons to the power level required by Adler's criteria. The amplified signal is then divided by 2:1 RF power divider. The divided signals are subsequently used for injection locking of both magnetrons through same length coaxial cables. The output power of the two magnetrons is combined in a symmetric H‐plane T‐combiner. Since both magnetrons follow the phase of a common injection source the instantaneous phase deviation in their injection‐locked responses is minimal, leading to a combining efficiency of 95%.

Refined InSAR tropospheric delay correction for wide-area landslide identification and monitoring

SAR Interferometry (InSAR) proves to be effective for investigating landslides. However, its measurement accuracy is largely limited by the complex atmospheric delay distortion in alpine valley regions, resulting in poor performance of landslides detection and monitoring. Particularly, the spatial atmospheric heterogeneity over wide areas cannot be accurately reflected by conventional empirical phase-elevation models or external data-based methods. In this study, we proposed a multi-temporal moving-window linear model (MMLM) to correct the tropospheric delay for wide-area landslides investigation. This is a linear regression model based on the elevation-phase relationship for modeling multi-temporal phases within a sliding local window. It mitigates the influence of local turbulent phase, local landslide deformation, and phase unwrapping error on parameter estimation, providing precise heterogeneous atmospheric corrections for wide-area InSAR landslide identification and monitoring. A simulation experiment was conducted to analyze the sensitivity of model parameters settings and evaluate the effectiveness of the MMLM model. Furthermore, we demonstrated the performance of the MMLM model through a comparison with the ERA5, GACOS, spatial-temporal filtering, and traditional linear model using descending and ascending Sentinel-1 data over the reservoir area of the Lianghekou hydropower station. Among the above-mentioned methods, the standard deviation of original unwrapped phases achieved the largest decrease of more than 35% and 50% after correction by the MMLM model for the descending and ascending Sentinel-1 tracks, respectively. In addition, the accurate deformation corrected by the MMLM model improved the landslides investigation, not only can help for delineating landslide boundaries in space but also retrieving movement evolution in time.

Ultrabroadband Circularly Polarized Antenna Array Based on Microstrip to SIW Junction

This communication presents a circularly polarized (CP) antenna array with ultrabroadband characteristics and a high gain for millimeter-wave applications. The CP is achieved by arranging eight linearly polarized (LP) tapered slot antenna elements in a circular arrangement based on sequential rotation (SR) techniques. The hybrid structure takes advantage of microstrip line (MSL) compactness in the feeding network and the capabilities of the substrate integrated waveguide (SIW) in antenna element design. A new T-junction MSL-to-SIW transition with a wide range of coupling ratios is used to serve as a wide power divider in the compact SR-feeding network. A detailed parametric study is carried out to demonstrate the effects of the coupling mechanism between the two transmission lines and to find the optimal configuration for the elements of the proposed antenna array. A tradeoff is made between antenna coupling, phase deviation, and overall size to achieve a compact structure with robust performances. An eight-element antenna array prototype is fabricated through the PCB process with a size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$57\times 48\times96$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Measured results show a 3 dB axial ratio bandwidth of about 49% over the entire 22.8–37.7 GHz range and a maximum gain of 18 dBi.

Analysis of physical performance during follicular phase vs luteal phase of menstrual cycle in eumenorrheic and young women

Background: Over the decade there has been increases in the number of women participating in exercise, physical and recreational activities. This active participation of women attributes to increase demand of physical performance. It has been seen that these performances have been affect over the different phases of menstrual cycle. Fluctuation of hormones in different phases can affect the performance in different ways. Aim: The present study aims to assess and compare the physical performance during follicular phase and luteal phase of menstrual cycle in eumenorrheic and young women. Methodology: After the study design was formulated, ethical clearance was taken from IEC. The study was a comparative type where the physical performance was compared in follicular phase and luteal phase. The study involved 40 regularly menstruating women between the age group 18-24 years. The participants were assessed for functional and sprint performance. The comparison of mean and standard deviation of follicular phase and luteal phase was done. Outcome Measures: Functional performance was measured by single hop test and sprint performance was measured with 30m sprint test. Results: The functional performance of follicular phase showed 120.7±13.35cm on left side and 125.4±12.27cm on right side whereas for luteal phase it was 124.1±12.73cm on left side and 127.8±11.83cm on right side. The sprint performance of follicular phase showed 7.75±0.54sec whereas luteal phase showed 7±0.6sec. Conclusion: The study concluded that eumenorrheic women showed better physical performance in luteal phase when compared to follicular phase.

Phase-generated carrier combined with the Hilbert transform for phase demodulation in frequency-scanning interferometry

Frequency-scanning interferometry (FSI) with an external-cavity diode laser (ECDL) is an effective technology for the absolute distance measurement of a target. The measurement accuracy of the FSI system is directly determined based on the phase extraction accuracy of an interference signal. However, because the optical frequency scanning of the ECDL exhibits nonlinearity, a large phase extraction error is introduced into the phase calculation result, which decreases the measurement accuracy. In this study, a composite algorithm for implementing phase-accurate demodulation is developed by combining the phase-generated carrier (PGC) technology and the Hilbert transform (HT) error compensation principle. In PGC technology, the demodulated phase contains the nonlinear error and quadrature phase deviation resulting from an amplitude ratio that is not equal to 1, and non-strict orthogonality of the two quadrature components. To compensate for these two errors, HT is utilized. The amplitude and phase of one of the two quadrature components are compensated by using the analytic signals on the complex plane, which ensures that the two quadrature components have the equal amplitudes and strict orthogonality. The effectiveness and stability of this composite algorithm are verified by a series of simulations and experiments. The experimental results indicate that the proposed method is capable of maintaining the single-cycle relative error of phase extraction within the 0.3% limit, thereby improving the measurement accuracy of the FSI system.

A 2.4–4-GHz Wideband 7-Bit Phase Shifter With Low RMS Phase/Amplitude Error in 0.5-μm GaAs Technology

This article presents a 2.4–4-GHz wideband 7-bit switch-type phase shifter (STPS) with a switch driver. Three switch-type phase shifting topologies are employed for the design of the phase shifter (PS), including the switched <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L/C$ </tex-math></inline-formula> structure, T-type structure, and high-/low-pass network. For minimizing the phase and amplitude deviations, an improved T-type structure with a switched filter structure has been proposed to boost the performance of the PS. Besides, a phase compensation cell also has been adapted to further decrease the phase error of the STPS. Based on the topology choice of each cell and the amplitude compensation among cells, a systematic design method is developed to extend the bandwidth of the PS. The proposed 7-bit STPS was implemented in the 0.5- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> GaAs pHEMT process. The measured root-mean-square (rms) phase error of the proposed STPS is less than 3.1° from 2.4 to 4 GHz and less than 1.5° at 2.8–3.7 GHz. The average insertion loss (IL) is 4.5–4.9 dB with an rms amplitude error of less than 0.34 dB. IP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1 dB</sub> is about 30 dBm. To the best of our knowledge, this PS achieves the highest resolution and the lowest rms amplitude error among the published GaAs/GaN PSs over a similar frequency band. The IL, bandwidth, and rms phase error of the proposed PS also show good performance.

Indirect Current Control Method Based on Reference Current Compensation of an LCL-Type Grid-Connected Inverter

NPC (neutral point clamped converter) is widely used in medium- and high-voltage grid connection because of its small power devices, simple overall structure, and easy control. This paper presents an improved indirect current control strategy for an LCL-type NPC. Firstly, the reference current is compensated to suppress the resonant peak of the LCL filter and improve the tracking accuracy of the output current. Then, with the relationship between state variables, the control structure is optimized by introducing the non-PLL control method, so that the sensors are reduced to only two sets. Finally, the traditional differential operator is improved to compensate the calculation delay in digital control. The experimental results show that the amplitude of thee grid-connected current is consistent with the reference value, the phase deviation is reduced from 7° to about 1°, and the transient response time is shortened to 1/3 of that of the traditional method.

Measurement of acylindrical surface with transport of intensity equation.

High-precision aspherical cylindrical (acylindrical) lenses are difficult to directly measure because of the phase deviation in the off-axis region. To achieve rapid and non-contact measurement of the acylindrical lens surface, a novel optical structure phase measurement, to the best of our knowledge, is presented in this work. Both common finite-difference and noise-reduction finite-difference methods were used for solving the transport of intensity equation (TIE) for reconstruction of high-resolution surface measurement. The results suggest that both common finite-difference and noise-reduction finite-difference methods can obtain good measurement results. The proposed method allows for the direct measurement of surface information without interference stitching. The accuracy of the TIE measurement has been verified through direct contact measurement.

Identification of start of combustion based on contribution level of principal component in vibration signal of cylinder head surface

The surface vibration signal measured from diesel engine cylinder head is caused by in-cylinder pressure (ICP) excitation and non-combustion excitations. These excitation response signals are coupled together, which increases the difficulty of identifying combustion information from the vibration signal. Furthermore, there always exists a phase deviation between the identified phase combustion parameter and the theoretical value, which decreases the recognition accuracy of combustion parameter. To accurately extract the combustion information, this paper firstly simulates the vibration signal caused by the combine of ICP, piston side pressure, piston slap and reciprocating inertial force of an SD2100TA diesel engine. Then, the principal component analysis (PCA) is introduced to analyze the contribution level of the combustion excitation response signal in the vibration signal under different working conditions. Meanwhile the influence of measuring point position and number on the contribution level is also discussed. Results show that the contribution level decreases gradually with the increase of the rotation speed and slightly increases with the increase of the torque. In addition, the contribution level is higher when the measuring point is farther away from adjacent cylinder. Finally, the relationship between the contribution level and the identified phase deviation of the start of combustion (SOC) is analyzed, and the deviation correction method is proposed. Results show that the maximum error of SOC after correction is within ± 1 deg.

Phase calibration for integrated optical phased arrays using artificial neural network with resolved phase ambiguity

Phase calibration for optical phased arrays (OPAs) is a key process to compensate for the phase deviation and retrieve the initial working state. Conventional calibration approaches based on iterative optimization algorithms are tedious and time-consuming. The essential difficulty of such a problem is to inversely solve for the phase error distribution among OPA elements from the far-field pattern of an OPA. Deep-learning-based technology might offer an alternative approach without explicitly knowing the inverse solution. However, we find that the phase ambiguities, including conjugate ambiguity and periodic ambiguity, severely deter the accuracy and efficacy of deep-learning-based calibration. Device-physics-based analysis reveals the causes of the phase ambiguities, which can be resolved by creating a tailored artificial neural network with phase-masked far-field patterns in a conjugate pair and constructing a periodic continuity-preserving loss function. Through the ambiguity-resolved neural network, we can extract phase error distribution in an OPA and calibrate the device in a rapid, noniterative manner from the measured far-field patterns. The proposed approach is experimentally verified. Pure main-beam profiles with&gt;12 dBsidelobe suppression ratios are observed. This approach can help overcome a crucial bottleneck for the further advance of OPAs in a variety of applications such as lidar.

A Reflection-Type Dual-Band Phase Shifter with an Independently Tunable Phase

This paper presents a design for a dual-band tunable phase shifter (PS) with independently controllable phase shifting between each operating frequency band. The proposed PS consists of a 3-dB hybrid coupler, in which the coupled and through ports terminate with the same two reflection loads. Each reflection load consists of a series of quarter-wavelength (λ/4) transmission lines, λ/4 shunt open stubs, and compensation elements at each operating frequency arm. In this design, a wide phase shifting range (PSR) is achievable at each operating frequency band (fL: lower frequency; fH: higher frequency) by compensating for the susceptance occurring at the co-operating frequency band caused by the λ/4 shunt open stub. The load of fL does not affect the load of fH and vice versa. The dual-band tunable PS was fabricated at fL = 1.88 GHz and fH = 2.44 GHz, and testing revealed that achieved a PSR of 114.1° with an in-band phase deviation (PD) of ± 8.43° at fL and a PSR of 114.0° ± 5.409° at fH over a 100 MHz bandwidth. In addition, the maximum insertion losses were smaller than 1.86 dB and 1.89 dB, while return losses were higher than 17.2 dB and 16.7 dB within each respective operating band.

Over-the-Air Calibration of Phase Shifter Network for Hybrid MIMO Systems

Phase shifter networks (PSN) are now widely used in multi-input multi-output (MIMO) systems for various purposes, from hybrid beamforming to strong interference mitigation. These applications require the phases of the PSN elements to be precisely calibrated, but the phase deviations always exist in practice. This paper proposes a novel over-the-air (OTA) approach to estimate the deviations of the phase shifters at each gear. Having some signal sources transmit pilot signals from unknown directions, we make the phases of the PSN shift across different gears and take the samples of the PSN output. Then the maximum likelihood (ML) estimation of the PSN errors which constitutes a three-way tensor, can be solved effectively by an iterative algorithm. The simulation results verify the effectiveness of the proposed algorithm and show that the root mean square errors (RMSEs) of the phase estimates can closely approach the Cramer Rao Bounds (CRBs).

Designing an ultrasonic array device to transport space particle suspension

Space particle suspension transport has the advantages to avoid adsorption loss, contact pollution, and signal interference, and has potential applications in the fields of cell self-assembly, controllable distribution of nanoparticles, and micro-Led mass transfer. Here, an ultrasonic array device was developed to obtain space particle levitation transport, and explore the suspension mechanism of the specific impact of the modulation signal on the space transmission and the mechanism of using the phase modulation signal to control the opposed linear transducer array to realize the space transportation. The suspension and directional transportation of ultrasonic standing waves are both non-contact and important means for processing without a certain container, and have a very broad application prospect in the fields of mechanical manufacturing, biochemical trace analysis, and droplet dynamics and so on. In this paper, aiming at the imperfect mechanism of space transportation and the complicated method of space transportation, we propose a new method of using phase modulation signals to control the array of opposite linear transducers to realize the space transportation of solid pellets. The transportation acceleration is used to characterize the stationarity in the transportation process, and the specific deviations of different phases of the modulation signal are set, so that the curves of acceleration change and position change of solid pellets in the transportation cycle can be drawn. The results show that when the phase deviation is <i>π</i>/2, it is the best to realize the stability of lateral transportation. When the phase deviation of coaxial array elements is set to <i>π</i> in longitudinal transportation, stable and long-distance transportation based on cycle period can be realized. The parametric model of 3D finite element is established, and the specific distribution of instantaneous sound pressure of dynamic sound field in space transportation is simulated. By comparing the experimental phenomena with different simulation results, we can find that the transportation process of solid balls is in good agreement with the movement of sound pressure nodes in sound field.

High-performance linear frequency-modulated signal generation based on optically injected semiconductor laser with dual-loop optoelectronic feedback

&lt;sec&gt;Linear frequency-modulated (LFM) waveforms have numerous applications in high-resolution radar detection, high-speed wireless communication, and high precision measurement. The generation of LFM microwave signals based on conventional electronic technologies is limited in their center frequency and bandwidth, which are usually less than a few gigahertz. Fortunately, the inherently large bandwidth offered by photonic technology is very hopeful of breaking through the electronic bottleneck. A variety of photonics-based approaches to generating the LFM waveforms have been reported, including the frequency-to-time mapping method and the external modulation method. However, these solutions suffer poor tunability or expensive RF sources. In recent years, the LFM waveform generation based on optically injected semiconductor lasers (OISLs) has attracted increasing attention. By introducing a low-speed electrical signal to control the period-one (P1) dynamics of an OISL, the LFM waveforms with a large bandwidth are generated. Nonetheless, the generated microwave signal has poor spectral purity, which restricts its many practical applications.&lt;/sec&gt;&lt;sec&gt;In this work, a high-performance microwave LFM waveform generation scheme based on an OISL with dual-loop optoelectronic feedback is proposed and demonstrated experimentally. In this scheme, the optical injection strength of an OISL is controlled first by a triangular-like voltage signal to generate LFM waveforms with a large bandwidth. Then, the quality of the generated LFM signal is comprehensively improved by introducing a delay-matched dual-loop optoelectronic feedback structure. Based on the Fourier domain mode locking principle (FDML) and the self-injection locking technique, both a short-delay optoelectronic feedback loop and a long-delay optoelectronic feedback loop are introduced to simultaneously improve the spectral purity and phase stability of the generated LFM signals. In the proof-of-concept experiment, by analyzing the spectral quality and phase deviation of the generated LFM signal, a comb contrast of 40 dB, a comb linewidth of 1 kHz, and a phase deviation ∆&lt;i&gt;φ&lt;/i&gt; of less than π/3 are simultaneously obtained. In addition, the parameters such as bandwidth and center frequency of the generated LFM signal generated can be flexibly tuned, and an LFM signal with a large bandwidth up to 8 GHz (18–26 GHz) is generated in the experiment. The proposed scheme features a simple and compact structure, high spectral quality and flexible tuning, thus may find applications in broadband radar and high-speed communication systems.&lt;/sec&gt;

Cross-Slotted Waveguide Array With Dual Circularly Polarized Radiation at W-Band

This article discusses the design of a cross-slotted waveguide array structure to be adopted for W-band communication between 84 and 86 GHz. Each array waveguide element contains 16 cross-slots along the broad wall to enable circularly polarized radiation behavior with a gain reaching up to 14 dBi and a cross-polarization isolation of more than 20 dB in the elevation plane. The design of the cross-slots is implemented with bent arms in order to accommodate them at an offset position from the waveguide narrow wall. Such position ensures the radiation of a circularly polarized wave. A waveguide-based feeding network with serpentine-shaped transitions is implemented to feed the eight-element cross-slotted array topology. The design of the feeding network ensures an equal power split and in-phase distribution between the eight elements with a phase deviation that does not exceed 20°. The overall cross-slotted waveguide array is prototyped as a proof of concept. The measured results show a maximum gain of 24.5 dBi for both polarization schemes. The measured half power beamwidth (HPBW) is 8° in the elevation plane and 12° in the azimuthal plane. The measured cross-polarization between the two circularly polarized schemes at both ports reaches a level of more than 26 dB. The comparison between the simulation and measurement results proves the validity of the proposed approach in achieving a high-gain dual circularly polarized structure for millimeter-wave communication.