Multiband Frequency Reconfigurable Antenna Research Articles

A Gain‐Enhanced Multiband Frequency and Pattern Reconfigurable Antenna for Wi‐Fi 6E and 5G New Radio Wireless Standards

A Gain‐Enhanced Multiband Frequency and Pattern Reconfigurable Antenna for Wi‐Fi 6E and 5G New Radio Wireless Standards

Design of multiband frequency reconfigurable antenna with switchable polarization states

AbstractThis paper presents the design of multiband frequency reconfigurable patch antenna with switchable radiation pattern and polarization states. The antenna design is based on a circular patch radiator with a pair of metallic strips placed on diametrically opposite sides of it. Circular polarization (CP) from the antenna is excited by etching a pair of slots with a coaxial feed. When the diodes are OFF, the antenna resonates at 4.2, 6.6 GHz, (C band) and 8.07 GHz (X band) and the main beam is located at 0⁰ with CP at X band. The resonance at 4.2 and 8.5 GHz are observed when one of the diode is ON. The main beam at X band is being shifted from −30⁰ to 0⁰ and +30⁰ in the elevation plane during the change in operating modes. Peak gain of the antenna is 6 dBi in all the operating modes.

Multi-band frequency reconfigurable antenna using EBG and parasitic patches

ABSTRACT This article demonstrated a compact reconfigurable microstrip antenna with a multi-band configuration. It resonates for three different frequency configurations, including the single and dual bands. The primary rectangular patch antenna resonates for WLAN (5.2 GHz center frequency) band. The reconfigurable electromagnetic bandgap (EBG) and parasitic patches near the feed line produce 4 and 6.33 GHz resonance. The defected ground structure is integrated with a PIN diode to make reconfigurable EBG, and it resonated at C band (4 GHz). The PIN diode switching configuration embedded with EBG and one square patch creates dual-band characteristics in wireless local-area network (WLAN) and International Telecommunication Union (ITU) bands. Other PIN diodes switching configurations with primary antenna and two other patches work for C and WLAN bands. The proposed antenna resonated at 4, 5.2, and 6.33 GHz frequencies with different switching configurations of the PIN diode. The simulated results of this novel antenna configuration verified with measured consequences for antenna parameters like reflection coefficient and radiation characteristics are also presented.

High gain wideband and multi-band on-demand reconfigurable antenna for modern wireless application

AbstractThis paper proposes a wide band and multiband frequency reconfigurable antenna that can operate in the UWB, GSM, GPS, 4G LTE, WLAN, and WiMAX bands. The antenna is made up of a trapezoidal-shaped monopole radiator, which was inspired by a rectangular monopole antenna. The ground plane is modified by embedding T and L-shaped slots to notch the desired operating frequency. The proposed antenna can switch to six different frequencies using RF PIN diodes, making it suitable for modern wireless applications. A multilayer frequency selective surface (FSS) reflector is presented to improve the gain of the proposed reconfigurable antenna. The low-profile design achieved a significant increase in gain while retaining the UWB antenna's excellent impedance bandwidth. Because of the use of the FSS reflector, the antenna's average peak gain has increased from 6 to 10.4 dBi. The proposed antenna has a wide switching capability, which validates its unique feasibility for high-speed multiple Internet of Things applications via a common embedded platform under various applications.

Design and fabrication of multiband reconfigurable copper and liquid multiple complementary split-ring resonator based patch antenna

The paper presents a multiband frequency reconfigurable microstrip patch antenna structure loaded by copper-based and water liquid-based superstrate resonators. The frequency tunability is achieved by three PIN diodes with the highest tunability of 320 MHz. The enhancement of gain is attained by the concept of superstrates in which the periodic structure implemented by copper-based and liquid-based split-ring resonators is considered for performance analysis. By loading the patch with the three copper-based and liquid-based split-ring resonators (SRR), the presented design achieves the maximum broadside directivities of 7.70 dB and 5.31 dB, and provides the maximum tunable frequency bandwidths of 250 MHz and 140 MHz, respectively. Out of all the configurations the copper-loaded three SRRs provide the peak gain of 9.11 dB. Comparison between simulated (by HFSS tool) and fabricated structures (using low profile material FR-4) is carried out in the frequency range from 6 MHz to 14 GHz for verification. The presented design opens a new way for achieving the different wireless communication applications such as satellite, aeronautical radio navigation, X-band synthetic aperture radar (SAR), etc.

Design and Experimental Analysis of Multiband Frequency Reconfigurable Antenna for 5G and Sub-6 GHz Wireless Communication.

A low-profile frequency reconfigurable monopole antenna operating in the microwave frequency band is presented in this paper. The proposed structure is printed on Flame Retardant-4 (FR-4) substrate having relative permittivity of 4.3 and tangent loss of 0.025. Four pin diode switches are inserted between radiating patches for switching the various operating modes of an antenna. The proposed antenna operates in five modes, covering nine different bands by operating at single bands of 5 and 3.5 GHz in Mode 1 and Mode 2, dual bands (i.e., 2.6 and 6.5 GHz, 2.1 and 5.6 GHz) in Mode 3 and 4 and triple bands in Mode 5 (i.e., 1.8, 4.8, and 6.4 GHz). The Voltage Standing Waves Ratio (VSWR) of the presented antenna is less than 1.5 for all the operating bands. The efficiency of the designed antenna is 84 % and gain ranges from 1.2 to 3.6 dBi, respectively, at corresponding resonant frequencies. The achieve bandwidths at respective frequencies ranges from 10.5 to 28%. The proposed structure is modeled in Computer Simulation Technology microwave studio (CST MWS) and the simulated results are experimentally validated. Due to its reasonably small size and support for multiple wireless standards, the proposed antenna can be used in modern handheld fifth generation (5G) devices as well as Internet of Things (IoT) enabled systems in smart cities.

A multiband and wideband frequency reconfigurable slotted bowtie antenna

A multiband and wideband frequency reconfigurable antenna is presented. A wideband from 3.5 GHz to 9.0 GHz is achieved by introducing one stripline in the middle of a slotted bowtie antenna, whereas multiband is obtained by integrating an additional two slotted arms at the end of bowtie-shaped. As a result, the antenna operated at multiband mode (1.7 GHz and 2.6 GHz) and wideband mode (3.5 GHz to 9.0 GHz) simultaneously. The reconfigurability of the antenna is attained through switches. Five states are achieved with three pairs of switches configurations. All results are presented and discussed, including S11, current distribution, radiation pattern, and gain. The antenna is suitable to be used in multimode communication systems.

Compact 3x1 Elements Reconfigurable MIMO Antenna for Cognitive Radio Applications

This paper presents, compact multiband frequency reconfigurable 3x1 MIMO antenna for cognitive radio applications. The antenna comprises 3-elements reconfigurable MIMO antenna and single element UWB sensing antenna. The frequency reconfigurability range under (S11 ≤ -10 dB) from 7-14.8 GHz using single PIN diode, while the UWB frequency range from 2.597-23.08 GHz. The antenna is designed and optimized to cover such wireless applications such as WiMAX, international telecommunication union (ITU), satellite, and broadband applications. The antenna is optimized using a Genetic Algorithm to operate in the MIMO and cognitive radio systems. The antenna dimensions for 3-elements MIMO antenna are 55 x 65 x 1.6 mm3 printed on an FR-4 epoxy substrate with relative dielectric constant εr = 4.3, loss tangent tan (δ) = 0.002 and 50 Ω microstrip feed line. The obtained simulated gain is ranging from 2.8-8.25 dB and the maximum simulated gain is 8.25 dB at 8.5 GHz. The return loss, Envelope Correlation Coefficient ECC, and Isolation are obtained to be less than -25 dB, less than 0.018, and less than -17 dB respectively. Detailed simulation results are explored and studied in this research. The CST software is used to simulate and optimize the proposed antenna.

New compact multiband inverted-L frequency reconfigurable antenna for cognitive radio applications

This paper presents, new compact and multiband frequency reconfigurable antenna for cognitive radio applications. A UWB sensing and reconfigurable communicating antennas are contained at the same substrate, where the UWB sensing antenna is an elliptical printed monopole antenna operates on frequency band from (2.65-22.112) GHz which can cover the UWB frequency band from 3.1 to 10.6 GHz, while the communicating antenna is an inverted-L frequency reconfigurable antenna operates on three bands of 1.49 GHz, 5.58 GHz, and 5.6 GHz under (S11 ≤ -10 dB) with a fractional bandwidth of 5.872%, 6.02%, and 6.05% respectively. The proposed antenna used to operate in two modes one for cognitive radio applications to cover WLAN applications at 5.5 GHz and 5.6 GHz and the second mode for wireless Ethernet, GPS synchronization, and Internet of Things that Matter (IoTtM) at 1.49 GHz. The frequency reconfigurability is obtained by using only a single RF switch (PIN diode) for changing the operating frequency. The antenna overall dimensions are 72 x 36 x 1.6 mm<sup>3</sup> printed on an FR-4 epoxy substrate of 4.3 relative-permittivity, loss tangent tan (δ) = 0.002 and 50 Ω micro stripline feed. The obtained simulated gain is ranging from 1.35 to 4.132 dBi. The S11 and isolation (S12) between the two antennas are under -20 dB and -17 dB respectively at the resonant frequencies.

Design of Multiband Frequency Reconfigurable Antenna with Defected Ground Structure for Wireless Applications

A novel printed rectangular shape, multi-band frequency reconfigurable antenna with defected ground structure (FRDGS) for multi standard wireless communication systems is designed in this article. The ground plane is modified by embedding U shaped slots with open ends and I shaped slot in short ends to realize the multi band frequency of the antenna and to improve the parameters of the antenna design. The two U shape slots are etched symmetrical to each other to reduce the cross polarization of the antenna. The DGS in the ground plane altered the modeling characteristics of transmission lines with the equivalent values of inductance, capacitance and resistance. Three PIN diodes are inserted in the ground plane to acquire the switching characteristics of multi-resonance frequency. Simulated and measured output clearly depict that the antenna proposed is efficient to change between twelve dissimilar resonant frequency bands centered at 1.36, 1.8, 3.0, 3.9, 5.0, 6.2, 6.4, 7.4, 7.9, 8.2, 8.4, 8.6 GHz through different states of modes over the frequency spectrum from 1.33 to 8.7 GHz. The parameters such as reflection coefficient, VSWR, 2D and 3D radiation pattern, bandwidth, peak gain, peak directivity, gain and directivity are simulated using Ansoft HFSS 17.0v. The proposed antenna finds application in various wireless communication system such as Wi-Fi (5 GHz), WLAN (5 GHz), WI-MAX, UWB (3.1–10.6 GHz) system, fixed mobile and satellite communication systems.

Compact reconfigurable PIFA antenna for wireless applications

This paper presents, new compact and multiband frequency reconfigurable planar inverted-F antenna (PIFA). The antenna is designed and optimized to cover mobile application devices like GPS, WLAN/Wi-Fi, WiMAX, 4G LTE, UWB, and satellite applications. The frequency reconfigurability is obtained by using only a single RF switch (PIN diode) for changing the operating frequency. The antenna dimensions are 45.6x39.6x1.6 mm 3 printed on an FR-4 epoxy substrate with relative dielectric constant er = 4.3, loss tangent tan (δ) = 0.002 and 50 Ω coaxial feed line. The proposed antenna has two patches connected by a single PIN diode. The antenna introduces nine resonant frequencies under (S11 ≤ -10 dB) which are: 0.980 GHz, 3.392 GHz, 3.924 GHz, 4.554 GHz, 5.82 GHz, 6.81 GHz, 7.305 GHz, 8 GHz and 8.105 GHz in the ON and OFF states of the PIN diode which are applicable to cover GSM900, WLAN/Wi-Fi, WiMAX, 4G LTE, UWB, and satellite systems. The obtained maximum simulated gain is 8.45 dB at 6.81 GHz. The lowest return loss is obtained to be -42 dB at 5.854 GHz. Detailed simulation and measurement results are explored and studied in this research. The CST software is used to simulate and optimize the proposed PIFA antenna. The proposed antenna has been fabricated and produced a good agreement with the simulation results.

Electromagnetic modelling of multiband frequency reconfigurable antenna for wireless communications

ABSTRACTThe present work aims to propose a new formulation by combining the moment method and generalized equivalent circuit's method (MOM-GEC) to study the performance of a frequency reconfigurable antenna commanded by a PIN diode(s) as switching component(s). This method makes it possible to reduce the 3D problems to an alleviate calculation in the discontinuity plane using the admittance operators. The antenna structure is excited by a localized voltage source and the PIN diode is introduced in the mathematical formulation by a surface impedance model. A parametric study is made to achieve a good approximation of PIN diodes longitudinal dimension ensuring the switch operation. Then we focus on the analysis of reconfigurable antennas controlled by one and two PIN diodes. The simulation results are in good agreement with those obtained by software simulation and they show that it is possible to shift the resonant frequency depending on the PIN diode state.

A Compact Grounded Asymmetric Coplanar Strip-Fed Flexible Multiband Reconfigurable Antenna for Wireless Applications

A compact grounded asymmetric coplanar strip (GACS)-fed flexible multiband frequency reconfigurable antenna with two PIN diodes is proposed. The investigated antenna is backed by a flexible polyamide substrate with compact dimensions of 24 mm $\times19$ mm and a thickness of 1.53 mm. The investigated antenna structure contains a monopole patch that facilitates operation for wireless LAN applications, whereas inverted L-shaped and F-shaped monopoles facilitate operation for Bluetooth and 5G NR applications. The investigated antenna operates at 2.4, 3.8, and 5.6 GHz with measured impedance bandwidths of 5.8%, 6.3%, and 6.6%, respectively, over the three frequency bands, thus facilitating coverage for Bluetooth, 5G NR, and WLAN standards. The two PIN diodes are employed to tune the investigated antenna among four modes, including a single band mode (WLAN 5.5 GHz), two dual-band modes (5G NR 3.8/5.6 GHz, and Bluetooth 2.48/5.6 GHz), and one multiband mode with Bluetooth (2.4 GHz), 5G New Radio (NR) N77 band (3.8 GHz), and WLAN (5.6 GHz) modes. The investigated antenna radiates unidirectionally with a peak gain of 3.73 dBi at 5.6 GHz. Measurements are carried out on the human body to investigate the behaviour of the wearable antenna. The simulated SAR values are in a safe limit of 1.6 W/kg for 1 g of tissue, according to the FCC. Moreover, the investigated antenna shows extremely low vulnerability to degradation in performance as a result of bending effects concerning impedance matching with acceptable acquiescence between measurements and simulations.

L/S Multiband Frequency-Reconfigurable Antenna for Satellite Applications

A novel multiband frequency-reconfigurable antenna is presented. The designed antenna can realize L-band single-frequency operation and S-band dual-frequency operation through electronic tuning. Annular ring and sawtooth patches are used as radiators for L/S-band operation and are excited by a broadband reconfigurable orthogonal network through the coupling of a T-shaped slot and a ring slot in the ground plane, respectively. By changing the bias of the p-i-n diodes loaded on the feed network, the operating frequency can be switched between the navigation state and the satellite link receiving state. A high tuning frequency ratio (1.64:1) is obtained. The simulated and measured results show good agreement. Good impedance matching (VSWR <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; $</tex-math></inline-formula> 1.3) and circular polarization characteristics (AR <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; $</tex-math></inline-formula> 3) are obtained in all three operating bands. Achievement of a highly reconfigurable frequency ratio of a circularly polarized antenna provides solutions for multifunction CP antenna aperture sharing.

Design and Analysis of Frequency Reconfigurable Microstrip Patch antenna for Multi Band Operations using PIN Diodes

Multiband reconfigurable patch antenna plays a vital role in wireless communication applications. By changing the current path on the patch a multiband reconfigurable antenna can be achieved. A simple multiband frequency reconfigurable microstrip patch antenna is presented in this paper. The proposed antenna structure is simulated in CST microwave studio. This antenna operates between 1.3 to 5.6 GHz with more than fifteen different frequencies. The antenna is analyzed for four different configurations. The designed antenna is resonating at five different frequencies (1.45 GHz, 2.36 GHz, 3.09 GHz, 3.6 GHz and 5.45 GHz) when both PIN diodes are ON. When PIN diode D1 is ON and D2 is OFF the antenna is resonating at 1.4 GHz, 2.22 GHz, 2.5 GHz, 3.08 GHz and 3.59 GHz. When D1 is OFF and D2 is ON the antenna is resonating at 2.34 GHz, 3.2 GHz, 3.62 GHz and 5.38 GHz frequencies. The slotted antenna or when both PIN diodes are in OFF condition antenna is resonating at 2.22 GHz, 2.49 GHz, 3.21 GHz, 3.6 GHz and 5.42 GHz. For each configuration the antenna parameters like gain, VSWR, directivity and radiation patterns are analyzed.

Stable‐multiband frequency reconfigurable antenna with improved radiation efficiency and increased number of multiband operations

In this study, a multiband frequency reconfigurable antenna is presented. The proposed antenna can switch among fixed GSM850/900 MHz, LTE1600/1700/1800 MHz and ISM2400 MHz bands through switchable, single, three double, and two triple band modes. The multiband operation is obtained using a spline-based radiator and two open-ended rectangular slot-resonators (RSRs). Three series configurations of PIN diode radio-frequency (RF) switches are integrated into RSRs to activate and deactivate it. The position of RSRs and RF switches is precisely optimised to obtain the desired operating bands and the input scattering parameter ( S 11) below −10 dB. RF switches #1–3 are turned ON and OFF to transfigure the current distributions on the radiator resulting in the frequency band-switching operation. It is shown that the integration of RSRs and PIN diode RF switches into the antenna structure degrades the radiation efficiency. To improve the radiation efficiency, the antenna is fabricated on a low dielectric constant multilayered substrate built using RT/Duroid 5880 laminates and an air gap. The increased multiband operation, good radiation efficiency, omnidirectional radiation pattern, and sufficient co-cross polarisation isolation are obtained in all operating bands. The prototype of the antenna is fabricated and fairly good agreement is seen amongst simulated and measured results.

FREQUENCY RECONFIGURABLE PATCH ANTENNA FOR 4G LTE APPLICATIONS

A compact printed multi-band frequency reconfigurable patch antenna for 4G LTE applications is presented in this paper (50 x 60 x 1.6 mm3). The antenna consists of W-shaped and Inverted-U shaped patch lines connected in a Tree-shape on the front side of the antenna. The back-side of the antenna contains a 90°-tilted T-shaped strip connected with an Inverted-L shaped strip which is shorted with a patch on the front side for increasing the electrical length to cover lower frequency bands. Frequency reconfigurability is achieved by inserting three switches i.e., PIN diodes. The most critical part of this work is the designing of RLC-based DC line circuits for providing the DC biasing to the PIN diodes used as switches and inserting them at optimum locations. This antenna is reconfigurable among eight different 4G LTE frequency bands including 0.9 GHz, 1.4 GHz, 1.5 GHz, 1.6 GHz, 1.7 GHz, 1.8 GHz, 2.6 GHz, 3.5 GHz and WLAN band 2.5 GHz. The antenna exhibits different radiation patterns having a different direction of peak gain at different frequencies and for different switching combinations. The antenna is simulated with CST, and a prototype is fabricated to compare the measured and simulated results with good accuracy.

Design of Frequency Reconfigurable Multiband Meander Antenna Using Varactor Diode for Wireless Communication

A compact multiband frequency reconfigurable meander antenna proposed for wireless communication systems is designed and described in this paper. A folded structure has been chosen due its good tradeoff between size, bandwidth and efficiency. The reference antenna is based on a meander patch structure radiating at F1=1, F2=1.94, F3=2.6GHz and optimized to be integrated in the Printed Circuit Board (PCB). In order to sweep the resonance frequencies, a chip capacitor was inserted between the meander patch printed on the top layer and a floating ground plane on the back one, in first case. Than in second case, by inserting a varactor diode to tuning electronically the resonance frequencies over wide bands. The measured results agree with simulations and good radiation properties were obtained. Realized prototype and related results are indeed presented and discussed.

A Compact, Tri-Band and 9-Shape Reconfigurable Antenna for WiFi, WiMAX and WLAN Applications

This paper introduces a novel 9-shaped multiband frequency reconfigurable monopole antenna for wireless applications, using 1.6 mm thicker FR4 substrate and a truncated metallic ground surface. The designed antenna performs in single and dual frequency modes depending on switching states. The antenna works in a single band (WiMAX at 3.5 GHz) when the switch is in the OFF state. The dual band frequency mode (Wi-Fi at 2.45 GHz and WLAN at 5.2 GHz) is obtained when the switch is turned ON. The directivities are: 2.13 dBi, 2.77 dBi and 3.99 dBi and efficiencies: 86%, 93.5% and 84.4% are attained at frequencies 2.45 GHz, 3.5 GHz and 5.2 GHz respectively. The proposed antenna has VSWR< 1.5 for all the three frequencies. The scattering and far-field parameters of the designed antenna are analyzed using computer simulation technology CST 2014. The performance of the proposed antenna is analyzed on the basis of VSWR, efficiency, gain, radiation pattern and return loss.

A Multiband Frequency Reconfigurable Rotated-L Slot Antenna

A multiband frequency reconfigurable rotated-L slot antenna is presented. The antenna is switchable between 4.61-6.20 GHz at nine different frequencies and capable to operates multi frequency at a time. The proposed antenna has a microstrip patch and two rotated-L slots, one slot is at patch and other is at ground plane. The two p-i-n diode is used in the ground plane rotated-L slot to achieve multi frequency agility. Results such as return losses, radiation patterns, gain and bandwidth are used to demonstrate the performance of the proposed antenna.