Conventional Antenna Research Articles

Transforming Linear to Circular Polarization on Horn Antennas by Using Multiple-Layer Frequency Selective Surfaces.

This article presents a technique for transforming the polarization of a pyramidal horn antenna by adding multiple layers of frequency-selective surfaces in front of the aperture, in order to rotate the direction of the electric field. Thus, two orthogonal components with the same magnitude, phase-shifted by 90°, are generated. Each frequency-selective surface consists of skewed λ/2 dipoles. Compared to other similar structures, our antenna system combines the field radiated from the horn aperture with the field scattered by parallel frequency-selective surface structures spaced on the same principle as that for designing a Yagi-Uda antenna array. The proposed horn antenna with multiple frequency-selective surfaces can be used as a feed element for a parabolic reflector antenna for maritime satellite communication systems in the X-band or in the lower part of the Ku band, or as part of a sensor for finding the direction of arrival of a wave, in order to orientate an antenna system. The concept was successfully validated on the basis of simulation and measurements. The proposed technique provides a close to unit axial ratio together with a 3 dB increase in gain compared to the conventional horn antenna, at low manufacturing costs.

A High Gain Embedded Helix and Dielectric Rod Antenna with Low Side Lobe Levels for IoT Applications.

In this paper, a novel embedded helix dielectric rod antenna is presented for high gain radiation with circular polarization (CP) and low side lobe levels for IoT Applications. Different from the conventional dielectric rod antennas, this proposed antenna is an integrated structure that combines the advantages of the helix and dielectric rod antennas. The presented antenna mainly consists of three parts: a tapered helix as primary feeding for CP, a dielectric rod with printed loops embedded for higher directivity, and a dielectric rod end for improving the gain further. After studying and analyzing the working principles of each part, an optimum design operating at 8–9.7 GHz is carried out as an example. A prototype is also fabricated and tested. The measured results show that the prototype can provide 18.41 dB maximum gain within the length of 7.7 λ. The side lobe level is below −20 dB, and the axial ratio is better than 1.14 dB in the whole frequency band. Compared with the traditional helix antenna and dielectric rod antenna with the same electric length, the presented antenna has a higher gain with a lower side lobe level and with good polarization purity.

Gain and bandwidth enhancement of slotted microstrip antenna using metallic nanofilms for WLAN applications

Structural modifications on microstrip patch antenna design for performance enhancement offer improvements and advantages only up to a certain limit. However, with the use of novel material in the patch area, the performance of a microstrip patch antenna can further be enhanced in terms of gain and bandwidth. In this paper, a nanomaterial-based slotted rectangular microstrip patch antenna is proposed for gain and bandwidth enhancement in Wireless Local Area Network (WLAN) applications. A conventional copper rectangular microstrip antenna (MSA) with a rectangular slot in the patch area is first fabricated and then nanomaterial is deposited in the slot area. Two types of metallic nanoparticulate thin films are deposited using Gold Nanoparticles (Au NPs) and a combination of alternate Silver-Gold-Silver Nanoparticles (Ag-Au-Ag NPs) in the slot area and the antenna parameters analyzed. A comparison between the conventional slotted MSA, and the fabricated antenna with the two different nanoparticulate thin films is presented. It is found that the Au NPs based antenna shows a 12.5 % improvement in bandwidth for a return loss of −31 dB and a 0.5 dB enhancement in gain with a nanomaterial film thickness of 264 nm. The composite Ag-Au-Ag NPs based antenna shows even better performance than the former one with an 18.75 % improvement in bandwidth for a return loss of −30 dB along with gain enhancement of 2 dB with a nanomaterial film thickness of 330 nm. Both the Au NPs and Ag-Au-Ag NPs based antennas are found to resonate at 5.89 GHz and 5.81 GHz showing an electrical size reduction of 32.09 % and 31.15 %, respectively compared to the conventional rectangular MSA.

초소형‧고효율 Fabry-Perot Cavity(FPC) 안테나의 설계 방법

We propose a novel design method for an ultrasmall high-efficiency Fabry-Perot cavity (FPC) antenna using an artificial magnetic conductor (AMC). Unlike conventional FPC antennas, which are approximately 2 λ, 3 λ in size, the proposed antenna has an ultrasmall size of 0.37 λ×0.37 λ, and it is enclosed by metallic walls blocking leaky waves. By installing an AMC on the metal walls, we significantly improve the radiation efficiency by up to 91 %. When the proposed antenna is utilized as an element of array antennas, it is expected to demonstrate a wide beam-steering range without grating lobes, owing to the narrow interval of the elements and the high steering accuracy resulting from the inhibition of undesirable couplings between the elements by the side walls.

Novel Dual-Mode Polarization Insensitive Wide Angular Stable Circular Ring Based Deca-Band Absorber for RCS and EMI Shielding Applications

A simple concentric circular ring resonator-based nonreciprocal deca-band absorber is demonstrated in this article. The design primarily consists of two frequency selective surfaces (FSSs) among one is a compliment to the other printed on either side of the 2.4 mm thin FR-4 dielectric substrate. It exhibits near-unity absorption effectively at ten different resonant frequencies over X-Ka bands with an average absorption efficiency of 94.6%. Surface plasmonic resonances are the reason behind the multiband absorption and are illustrated with current profiles at resonant frequencies. The performance is angular stable for both transverse electric and transverse magnetic oblique incidences up to 60 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sup> . The design is compact with a structural periodicity of 0.210 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{\lambda }}}_{\boldsymbol{o}}$</tex-math></inline-formula> and thickness 0.07 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{\lambda }}}_{\boldsymbol{o}}$</tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{\lambda }}}_{\boldsymbol{o}}$</tex-math></inline-formula> is the lowest resonant peak's free-space wavelength. The 20×20 array of the design prototype is fabricated, and the measured results agree with the full-wave analysis. Bistatic radar cross section (RCS) analysis of the proposed absorber is evaluated along with a conventional microstrip patch antenna at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</i> -band. Since the absorber design is based on complementary FSSs, it can also be utilized as a reflector for the not absorbing frequencies. The novelty lies in the utilization of the dual-side of the substrate made this design compact with a greater number of absorption peaks and good angular stability, making it potential for real-time RCS, and electromagnetic interference and shielding applications.

An Antenna Based on Three Coupled Dipoles With Minimized E-Field for Ultra-High-Field MRI

In this work, we demonstrate an approach for local reduction of the electric field amplitude of the transmitted radio-frequency signal in ultrahigh-field magnetic resonance imaging (MRI). We excite a suitable combination of three coupled dipole hybrid resonances composing a single transmit antenna array element. Using numerical optimization, we designed a feeding network for three coupled dipoles placed over an electromagnetic phantom mimicking a human body. This network of discrete elements provides the appropriate amplitudes and phases of three dipole currents excited by a single input port. It allows controlling the electric field distribution in the vicinity of the antenna. Our goal was to obtain a minimum of the electric field at the given relatively small depth inside the phantom, where body implants are typically located while keeping a tolerable level of the magnetic field toward the phantom’s center. We designed and manufactured a three-dipole antenna prototype optimized for MRI of the human body at 7 T (proton Larmor frequency of 298 MHz). The experimental validation showed a 40 dB reduction of the electric field amplitude at a depth of 4 cm compared to a conventional single-dipole antenna. The coupling network can be rearranged to target different depths. Therefore, a principle of electric field minimization at a controllable position inside the body has been shown, which may be useful for designing transmit MRI antennas with improved safety of implants.

Characteristic Mode Inspired Single-Plate Unidirectional Antenna Using Complementary Characteristic Radiation

Based on characteristic mode theory (CMT), a novel single-plate complementary antenna with a unidirectional radiation pattern is proposed in this communication. The proposed antenna is composed of an isosceles right triangular conductive slab (IRTCS), three inductive coupling elements (ICEs), and a feeding network. By exciting two complementary current modes of IRTCS simultaneously, the radiation of IRTCS can be tailored. More specifically, ICEs can stimulate the electric dipole and magnetic dipole current modes of IRTCS concurrently through appropriate excitation, thereby realizing an endfire radiation pattern by combining the two complementary characteristic fields with suitable modal weighting coefficients (MWC). For proof of concept, a prototype is fabricated, and the measured results demonstrate that a good unidirectional radiation pattern is achieved with a front-to-back ratio (FBR) larger than 20 dB, which verifies the feasibility and reliability of the proposed method. Compared with the conventional complementary antennas or Huygens source antennas which need two different radiating sources to realize the electric and magnetic dipole radiations individually, the proposed method reuses the radiating aperture and achieves the unidirectional radiation by a single radiating aperture.

Reduced-Size Series-Fed Two-Dipole Endfire Antenna

The conventional series-fed endfire dipole antenna has a wide impedance bandwidth and is inexpensive to manufacture. However, it has a disadvantage: its size is large because of the large inter-dipole spacing, which is required to satisfy the endfire condition for good antenna radiation characteristics. Here, we propose a two-dipole endfire antenna with a reduced size. The miniaturized endfire antenna was designed using a meander line to reduce the interdipole spacing while ensuring that the endfire condition was satisfied. Furthermore, the overall width of the antenna was reduced using a bent dipole and a corrugated ground plane. The electrical size of the proposed antenna was only 0.33

Stable phase‐centre horn antenna using 3D printed dielectric rod for aperture efficiency improvement of space‐fed antennas

The design strategy to stabilise the phase centre (PC) of the conventional horn antenna using a shaped dielectric rod is presented for aperture efficiency improvement of space-fed antennas. In most practical horn antennas, PC location has significant variations with frequency leading to phase error loss and aperture efficiency reduction over the bandwidth of interest. To overcome this drawback, based on physical reasoning, shaped dielectric rods with appropriate excitation mode are designed and placed on the aperture of conventional rectangular and conical horn antennas. The simulation results show that using a shaped dielectric rod inside the horn antenna leads to a decrease in phase-centre variations versus frequency without disturbing the radiation pattern and reflection coefficient. To investigate the performance, a conical corrugated horn antenna loaded by a conical tapered dielectric rod is used as a feed of the transmitarray antenna. Using a shaped dielectric rod fabricated by 3D printing technology, the PC variations of the proposed horn decrease from 1.06 λ to 0.08 λ over the X-band (λ at 8 GHz). The measurement of the fabricated transmitarray antenna shows an improvement of maximum aperture efficiency from 55% to 64.7% at 10 GHz. The aperture efficiency bandwidth above 50% level is also increased from 1 to 2.2 GHz.

The Development of Broadband Microstrip Patch Antenna for Wireless Applications

The small volume of microstrip antennas has low production costs and easy production, which has accelerated the work in this area. The disadvantages are narrow bandwidth and low gain. In wireless communication, antennas with low return loss and high bandwidth are required. The bandwidth and power gain of the microstrip patch antennas should be increased optimally. This article presents the design of the broadband microstrip patch antenna operating in the ISM 2.4 GHz band (2400-2485 MHz). The study includes three-dimensional antenna model, simulation phase and fabrication / measurement phase. For the low cost of the antenna, FR-4 with the relative dielectric constant 4.3 and the loss tangent tan 0.02 is preferred as the substrate material. Dielectric material thickness is determined as 1.6 mm. The length of the feed line and the dimensions of the rectangular patch were found by mathematical calculations with the transmission line model. There are slots on the antenna, which is a very simple method in order to improve the bandwidth, gain and directivity parameters of the antenna. In the article, four different designs are presented, the results are compared and the proposed antenna has 979 MHz bandwidth and 2.68 dBi directivity gain at -10 dB at the resonance frequency of 2.316 GHz. The changes made in the antenna design have improved the results such as gain and bandwidth compared to the conventional microstrip patch antenna. The proposed antenna is suitable for use in mobile communication.

Transmit antenna selection for spatial modulation based on machine learning

The next-generation of networks should have better spectrum and energy efficiency. These competing design parameters can be dealt with spatial modulation (SM). Transmit antenna selection (TAS) strategies can enhance the average bit error rate (ABER) performance of SM. The purpose of this research is to examine the employment of machine learning (ML)-based TAS schemes for SM. The conventional Euclidean distance-based antenna selection (EDAS) scheme offers optimal performance at the expense of computational complexity. This paper discusses the application of four different ML algorithms to SM-TAS: Support vector machines (SVM), K-nearest neighbour (KNN), decision tree (DT), and naïve Bayes (NB). With reduced complexity, an SVM-based TAS scheme for SM can offer a minimum gain of ∼3.4 dB over SM with no transmit antenna selection (SM-NTAS). Furthermore, the ABER performance of all schemes is tested with a higher modulation order and a number of transmit antennas. In every scenario, ML-based TAS schemes outperform SM-NTAS in terms of ABER performance.

Film-penetrating transducers applicable to on-chip reservoir computing with spin waves

We have proposed a spin-wave transducer structure named film-penetrating transducers (FPTs). FPTs penetrate an on-chip magnetic film for a spin-wave transmission medium and allow flexible spatial arrangements of many exciters/detectors due to their zero-dimensional feature. We constructed four device models with different spatial arrangements of FPT/conventional exciters using a 10-nm-thick ferrimagnetic garnet film with a central FPT detector. We performed numerical experiments that combine electromagnetics with micromagnetics including thermal noise at 300 K. We evaluated important device features of FPTs, such as the signal-to-noise ratios (SNRs), input/output signal transmission efficiencies, and nonlinear phenomena of spin waves. We applied in-phase sinusoidal input currents with various amplitudes and frequencies and altered the damping strengths near the film boundaries. We obtained sufficient SNRs for the practical use of FPTs and revealed that FPTs have both higher transmission efficiencies and nonlinear strengths than conventional antennas, as the input frequency approaches the ferromagnetic resonance frequency of the film. Moreover, we observed and analyzed various nonlinear phenomena of spin waves, including beats in the time-domain waveform, components of integer harmonic frequencies, wide-range scatterings of inter-harmonic frequencies, and frequency doubling in spin precession. These characteristics probably originate from various device effects: FPTs effectively excite dipolar spin waves with large-angle precession, propagating spin waves reflect from the film boundaries, and spin waves dynamically and nonlinearly interfere with each other. This study demonstrated that FPTs have promising features for both their applications to reservoir computing and the studies on the physics of nonlinear and space-varying spin waves.

Design and SAR Analysis of a Dual Band Wearable Antenna for WLAN Applications

This paper presents the design of three types of dual band (2.5 &amp; 5.2 GHz) wearable microstrip patch antennas. The first one is based on a conventional ground plane, whereas the other two antennas are based on two different types of two-dimensional electromagnetic band gap (EBG) structures. The design of these two different dual-band EBG structures using wearable substrates incorporates several factors in order to improve the performance of the proposed conventional ground plane (dual band) wearable antenna. The second EBG with plus-shaped slots is about 22.7% more compact in size relative to the designed mushroom-like EBG. Subsequently, we have demonstrated that the mushroom-like EBG and the EBG with plus-shaped slots improve the bandwidth by 5.2 MHz and 7.9 MHz at lower resonance frequencies and by 33.6 MHz and 16.7 MHz at higher resonance frequencies, respectively. Furthermore, improvements in gain of 4.33% and 16.5% at a frequency of 2.5 GHz and improvements in gain of 30.43% and 4.57% at 5.2 GHz have been achieved by using the mushroom-like EBG and EBG with plus-shaped slots, respectively. The operation of the conventional ground plane antenna is investigated under different bending conditions, such as wrapped around different rounded body parts. The proposed conventional ground plane antenna is placed over a three-layered (flat body phantom (chest)) and four-layered (rounded body parts) tissue models, and a thorough SAR analysis has been performed. It is concluded that the proposed antenna reduces SAR effects (&lt;2 W/kg) on the human body, thereby making it useful for numerous critical wearable applications.

Array design for mm-wave UAV-assisted cooperative communications with simultaneous wireless information and power transmission

High performance UAV-assisted communications system using simultaneous wireless information and power transmission (SWIPT) in mm-wave band is presented. UAV is a moving relay powered from a ground source through a power-splitting mechanism. In mm-wave band we utilize antenna array to increase the antenna gain while keeping array size small and practical. The radiation pattern of the UAV antenna is continuously adjusted to peak towards the source and destination. Two array geometries, a line and a cross, are designed for UAV antenna. We achieve near optimal pattern, utilizing innovative low power switches instead of phase shifters which are high power consuming components and using them here defies the purpose. We maximize the end-to-end cooperative throughput by optimizing the UAV power profile, power-splitting ratio profile, antenna weights (0, 1), and UAV trajectory for amplify-and-forward (AF) protocol. We consider two cases. Case1: UAV transmits and receives data simultaneously along two predefined trajectories. The antenna weights for line and cross arrays are optimized utilizing genetic algorithm. The power profile and, power-splitting ratio profile are also optimized using the penalty method. Case2: UAV accumulates the data and power along an optimal trajectory until it reaches the vicinity of target, when it transmits data at high bit rate. Here we define the optimization of parameters mentioned in Case1, while at an optimal point along the trajectory, as sub-problem1, and finding the next optimal point as sub-problem2. Sub-problem1 is solved using the genetic algorithm and dual decomposition method. Sub-problem2 is then solved using successive concave optimization. The overall problem, i.e. cooperative throughput, is solved by reciprocal iteration over the two sub problems. The simulation results show the proposed mm-wave band cross array antenna and switches can overcome the high frequency propagation losses, hence, achieving higher power harvest and data rates. The achieved higher data throughput outperforms the conventional single antenna low frequency systems.

Coverage and Meta Distribution Analysis in Ultra-Dense Cellular Networks With Directional Antennas

This article proposes a one-tier ultra-dense cellular network framework based on the characteristics of directional beamforming to explore the downlink signal-to-interference ratio (SIR) performance. The features of the proposed cellular network include: small base stations (SBSs) are equipped with directional antennas; the beam boresight directions of antennas are adaptively adjusted with the locations of users on the two-dimensional horizontal plane while the boresight directions are perfectly aligned with their associated users. In addition, an angle fading model, which follows from the exponential distribution, is developed to simulate the signals attenuation of interference links. The angle fading of the interference signals depends on the angle offset between the locations of users and the beam boresight directions of their interfering SBSs. With the assistance of stochastic geometry, the analytical expressions of coverage probability and average ergodic rate are derived by combining with the probability density function of angle offset variable. Then, the meta distribution of SIR is obtained to capture the performance changes of individual links for users. The numerical results indicate that the performance advantages of the proposed directional network obviously exceed that of the conventional isotropic antennas case. Monte-Carlo simulations validate the correctness of numerical results.

Quantum Shot Noise Limit in a Rydberg RF Receiver Compared to Thermal Noise Limit in a Conventional Receiver

Electromagnetically induced transparency in a vapor of Rydberg atoms can be used for radio frequency (RF) electric field sensing. Such sensors can be traceable, tunable, compact, and electrically passive. One application for these electric field sensors is as a receiver for RF communications, converting a 5G transmission in free space to a modulated optical signal in a fixed network. Different figures of merit are used for an electric-field sensor and a 5G receiver; so it is not straightforward to determine under which operating conditions a Rydberg RF receiver may outperform a conventional antenna and receiver. Here, we consider two fundamental limiting sources of noise, calculating the quantum shot noise limit in a Rydberg RF receiver and comparing this to the thermal noise limit in a conventional macroscopic receiver. For a typical experimental setup, we show that the quantum shot noise can only fall below the thermal noise floor when the symbol rate is below 1−2 MSymbol/s. Higher order signal modulation will be needed to further increase data rate whilst using this constrained symbol rate to limit the fundamental noise floor.

Low-Cost Lens Antenna Design for Microwave Moisture Detection

In this study, a novel Vivaldi antenna with dimensions of 100 mm × 85 mm × 1.6 mm, designed for a moisture measurement system, is built to enhance the gain of conventional Vivaldi antennas in the low-frequency band to suit the needs of moisture detection. The fence structure and choke slot are modified to enhance the antenna’s radiation properties in the low-frequency band, and simulation is performed to determine how different structural parameters affect the antenna’s performance. The results show that in the frequency band of 5-6 GHz, the voltage standing-wave ratio (VSWR) of the antenna is less than 2, and the gain at 5.8 GHz reaches 16.2 dBi after installing the lens. Compared with conventional unmodified Vivaldi antennas, the gain at 5.8 GHz increases by approximately 6.11 dBi. The antenna is then processed and measured, and the measured results are in good agreement with the simulated results; hence, the antenna can be widely used in the field of moisture detection.

Motion-based microwave tomographic measurement device for three-dimensional coverage in a magnetic resonance system.

We have developed a fully 3D data acquisition system for microwave breast imaging which can operate simultaneously inside a magnetic resonance imaging (MRI). MRI is used regularly for breast imaging to distinguish tumors from normal tissue. It generally has poor specificity unless used with a gadolinium contrast agent. Microwave imaging could fill this need because of the good endogenous tumor:normal tissue property contrast, especially in light of safety concerns for gadolinium. The antenna array consists of 16 monopole antennas positioned in a horizontal circle surrounding the breast which can then be moved vertically for 3D coverage of the breast. The tank system materials were chosen to minimize artifacts in the MR image within the specific shared imaging zone. The support rods are stainless steel, albeit positioned sufficiently far from the imaging target to have little effect. The mechanical motion parts are all 3D printed plastic. Unlike many conventional antennas, the monopoles consist of just the center conductor and insulator of the coaxial cable, making it one of the least possible metallic structures. Data were acquired both inside and outside of the MR bore to confirm that the MR bore did not have adverse effects on the microwave imaging process. The imaging tank was filled with a mixture of glycerin and water to both provide a reasonable property match to the phantom and to highly attenuate the fields which also acted to suppress multi-path signals. Microwave images were reconstructed using our Gauss-Newton scheme combined with a log transformation for a more linear convergence. MR images were also acquired to assess the effects of the microwave tank structures on the imaging. The microwave measurement data were acquired in log magnitude and phase format at 200 MHz increments from 700-1900 MHz. Each antenna acted sequentially as a transmitter while the complement of 15 acted as a receiver. The single frequency images were reconstructed using a Gauss-Newton iterative technique with a standard log transformation to linearize the process. The data showed that the signal strengths were between 7-10 dB lower for the case when the array was inside the MRI versus when not. Notwithstanding, the image quality was still high because of the significant signal to noise ratio. The reconstructed images in both situations demonstrated good 3D object recovery of the vertically size and shaped varying object. The MR images were not adversely affected by the presence of antennas or feed structures. We have demonstrated that our technique can recover high-quality images of a 3D varying object within an MRI system. Compatibility issues have been addressed for both the microwave and MRI systems. The reduced SNR for the case operating in the MRI did not adversely affect the images. To the best of our knowledge, this is the first example of a microwave imaging system operating in an MRI with full 3D volumetric capability.

Miniaturized Bandwidth Reconfigurable Yagi-Uda Antenna for Wireless Applications

We propose a miniaturized Yagi-Uda antenna with a reconfigurable operating bandwidth. The antenna miniaturization and bandwidth enhancement are achieved based on manipulating the shape and the position of the antenna reflector and director. Indeed, by coupling effects, three resonances are combined to broaden the impedance bandwidth without affecting much the radiation characteristics. On the other hand, the reconfigurability function is ensured based on the insertion of one varactor diode onto the antenna reflector. The measured results reveal that the proposed design has the merits of a miniaturized one-layer design with 75% size reduction compared with the conventional antenna, a measured peak gain of 4.57 dBi, a peak efficiency of 97%, a smoothly tunable relative bandwidth of 10% to 30%, and a simple DC-bias network with less lumped components. The proposed antenna may find its use in some wide-band unidirectional wireless applications covering the bandwidth 0.99 GHz to 1.34 GHz, for instance, in cognitive radio applications where the operating bandwidth can be reconfigured, accordingly.

Temperature Self-Compensation Method for Crack Length Measurement Based on a Microstrip Antenna Sensor

A temperature self-compensation method for the microstrip antenna sensor is innovatively proposed to reduce the measurement error associated with temperature variation. Temperature compensation is achieved by inserting a layer of compensation substrate in the resonant cavity of the antenna sensor. The compensation substrate with a thermal coefficient of the dielectric constant opposite that of the sensor substrate is designed to offset the frequency variation of the sensor. The design parameters of the sensor are obtained from multi-layer substrate theory and microstrip antenna theory. The temperature compensation performance of the sensor is experimentally and numerically analyzed to validate the proposed method. The results show that the microstrip antenna sensor proposed in this paper provides more accurate measurement results of the structural crack length with an identification error of ±0.2mm within the temperature range of 0 to 60 °C. This reduces the measurement error of the crack length in a multi-temperature environment by more than 95%, relative to that of conventional microstrip antenna sensors.