Frequency Reconfigurable Monopole Research Articles

Active frequency selective surface-based 360° beam steering in two switchable frequency bands independently

ABSTRACT A reconfigurable antenna with frequency agility and pattern-switching ability is presented in this paper. The proposed design comprises a planar and compact frequency reconfigurable monopole antenna and an active frequency selective surface (AFSS) with reconfigurable transmission and reflection properties in dual bands. The AFSS screen is divided into four sections and each section is composed of four FSS elements with only one PIN diode in each unit cell. The monopole antenna, which is situated at the center of the box-shaped AFSS to illuminate , can reconfigure its resonating frequency between 2.5 and 3.6 GHz with the help of only one PIN diode. With the help of this transformation ability of AFSS behavior electronically, the pattern can be steered across the entire X–Z plane in eight steps at two different operating frequencies independently. This antenna can be very useful in various wireless applications such as drones, small base stations, etc.

Compact 3-bit Frequency Reconfigurable Monopole Antenna Realized with a Switchable Three-Line Section

This work proposes a compact 3-bit frequency-reconfigurable monopole antenna covering a broad reconfigurable range by inserting a switchable three-line section (STLS). The design starts with a conventional quarter-wavelength monopole line antenna, which is then replaced by a novel structure, the STLS. The STLS is composed of three parallel-connected lines with different lengths. Accordingly, three RF p–i–n diodes are introduced in the STLS to achieve binary reconfiguration. After all parameters of the antenna have been optimized, it will eventually output 2N = 8 (N is the number of switches) independent working states with different equivalent lengths and a reconfigurable working frequency. The number of states in a binary reconfigurable antenna is optimally large in relation to the number of switches used, which means that it can be extremely convenient for digital control of switching all the states and capable of decreasing the number of RF p–i–n diodes we used, thereby minimizing the manufacturing cost and loss of diodes. A prototype antenna is fabricated and tested, and the measurement results agree well with the simulation results, validating the good features, such as a large reconfigurable switchable frequency range from 0.95 GHz to 2.45 GHz with considerable working bandwidth varying from 40 MHz to 540 MHz for each state, simple structure, and a compact size of 70 × 40 mm2, which can be appropriately used for a multi-radio wireless system and handheld devices. All the states have a similar monopole radiation pattern with a good maximum efficiency and an acceptable peak gain according to its compact size.

Reconfigurable Planar Monopole Antenna for Fifth-Generation Mobile Communication System

A frequency reconfigurable planar monopole antenna for fifth-generation (5G) mobile communication terminal equipment is presented. The proposed antenna uses a meandered monopole, branch resonance and other techniques to make the antenna resonant in multiple frequency bands. The antenna is compact in size (115 mm × 55 mm × 0.8 mm) and has a longitudinal length less than one-tenth of the resonant wavelength (working at 1.79 GHz). The pin diode is designed between the planar meandered monopole antenna and branch. The current path of the high-frequency current on the antenna can be easily controlled by controlling the DC bias voltage of the diode, and the operating frequency of the antenna is switched between three frequency bands. The antenna is fed directly through a 50 Ω matched transmission line. The measured data of the antenna in the anechoic chamber show good consistency with simulation data. The radiation pattern of the antenna shows good omnidirectional characteristics and good frequency characteristics, with a maximum radiation gain of 13.6 dBi. Experimental results demonstrate that the antenna can meet the design requirements of 5G communication.

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.

Frequency reconfigurable antenna actuated by three-storey tower kirigami

This paper proposes a frequency reconfigurable monopole antenna using kirigami technology. The monopole antenna is designed on a three-storey tower and the tower is transformed from a ground mode to the three-storey structure by kirigami. For the ground mode, the horizontal monopole pattern is realized on a two-dimensional plane or floor. For the tower mode, the monopole pattern is transformed to a three-dimensional vertical monopole that is realized on the pillars. In the process of transformation of the tower, the resonant frequency of the antenna is changed because this frequency is determined by the monopole length. The proposed idea is numerically and experimentally demonstrated by realizing the antenna using polyethylene terephthalate (PET) film. The resonant frequency changes from 420 to 530 MHz when the antenna is transformed from the ground to tower modes, respectively. The measured peak gains are −5.08 dBi and 0.76 dBi at the ground and tower modes, respectively. In this work, an architectural three-storey tower is applied to antenna design, and its frequency reconfigurability is achieved by kirigami transformation.

Frequency reconfigurable monopole antenna with harmonic suppression for IoT applications

This work proposes a new reconfigurable printed monopole antenna for IoT devices working with the promising wireless technology Wi-Fi 6. Based on effective resonant length value, the antenna has the ability to reconfigure its operating band between 2.4 GHz and 5 GHz ISM bands. Therefore, the designed antenna works as an RF band-pass filter which reduces receiver complexity and supports network scalability. One PIN diode with complete biasing circuit is integrated to the antenna radiator to obtain re-configurability. Furthermore, two stubs are added to the antenna structure in order to suppress harmonic component which appears near to the higher band (5 GHz) when antenna forced to work at the lower band (2.4 GHz). The design built over commercially available FR-4 substrate with a compact size of (33.5x16x1.6) mm 3 . CST software is used to simulate antenna performance in terms of flection coefficient, radiation pattern, efficiency, and gain.

Compact asymmetric fractal frequency and pattern reconfigurable monopole antenna

A compact frequency and pattern reconfigurable monopole for LTE and WLAN applications is presented. The antenna consists of an asymmetric fractal patch which is derived from a bow-tie antenna and optimized using Pattern search algorithm. The antenna operates at 1.8 GHz and 5.2 GHz frequency with a different radiation pattern for each case. A single PIN diode is used to achieve frequency and pattern reconfigurability. The antenna is simulated using Ansoft High Frequency Structural Simulator (HFSS) software and fabricated on FR4 substrate with the relative permittivity of 4.4; having size of 30 mm * 24 mm and thickness of 1.6 mm.

Performance analysis of silicon-based frequency reconfigurable monopole

A silicon-based high integration frequency reconfigurable monopole is demonstrated in this paper. To meet the development of the modern communication systems, a high resistivity silicon wafer is used as the monopole substrate to improve the integration of antenna systems, and manufacturing technology for this monopole is compatible with the traditional silicon machining processes. Based on the optimized structural parameters, the monopole’s resonant frequencies at 3.73 GHz and 3.85 GHz have been achieved by changing the active length of this antenna, and the radiation efficiencies of the reconfigurable antenna at two working states are 78.66% and 73.17%, respectively. Other radiation characteristics of this monopole also shown good performance in this paper. Simulation and experimental results show excellent agreement, which have shown the validity of the antenna design. Therefore, this antenna is more suitable for modern wireless communications, and a novel high integration solid state plasma reconfigurable antenna based on silicon-based surface PiN diodes will be designed for further investigation.

Frequency reconfigurable monopole antenna with DGS for ISM band applications

Abstract In this article a compact frequency reconfigurable antenna is presented for wireless communication applications of industrial, scientific and medical band (ISM). The proposed antenna model is designed with the dimensions of 58mm×48 mm on FR4 epoxy of dielectric constant 4.4 with the thickness of 0.8 mm. The proposed antenna consists of defected T-shape ground plane, which acts as a reflector. In the design of frequency reconfigurable antenna, BAR 64-02V PIN diodes are used as switching elements and antenna is fed by microstrip transmission line. The proposed antenna can switch at different frequencies (2.5 GHz, 2.3 GHz and 2.2 GHz) depending on the biasing voltage applied to the PIN diodes. The current antenna showing VSWR < 2 in the operating band and providing peak realized gain of 3.2 dBi. A good matching obtained between expected and the measured results.

Compact CPW-fed spiral-patch monopole antenna with tuneable frequency for multiband applications

A frequency reconfigurable monopole antenna with coplanar waveguide-fed with four switchable for multiband application is reported. The monopole antenna includes square-spiral patch and two L-shaped elements. The number of frequency resonances are increased by adding square spiral. In the reported antenna, two PIN diodes are used to achieve the multiband operation. PIN diodes embedded on the spiral patch can control the frequency resonance when they are forward-biased or in those off-state. The final designed antenna, with compact size of 20 × 20 ×1 mm3, has been fabricated on an inexpensive FR4 substrate. All experimental and simulation results are acceptable suggesting that the reported antenna is a good candidate for multiband applications.

A Frequency Reconfigurable UWB Monopole Antenna with Slotted Ground Structure

A Frequency Reconfigurable UWB Monopole Antenna with Slotted Ground Structure

Design Simulation and Fabrication of a Dual Band Frequency Reconfigurable Monopole Antenna for Wi-Fi and WiMAX Applications

Nowadays, wireless systems require compact multi band antennas that can dynamically change some of its fundamental parameters such as frequency band, polarization and radiation pattern. The novelty of the proposed work lies in using two conducting strips that are perpendicular to each other. The longer strip resonates at 2.4 GHz and the shorter strip resonates at 3.5 GHz. The length and width of the Ground plane is made equal to length of the main arm and length of the side arm respectively. The results are obtained by simulating the antenna structure using simulation tool Ansoft HFSS v15.0. The Simulated antenna Gains were 6.2364 dBi and 7.1758 dBi for frequencies of 2.4 GHz and 3.5 GHz respectively. The antenna dimensions are 50 × 25 × 1.6 mm3 on a 1.6 mm thick FR-4 substrate.

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.

Design of a frequency reconfigurable monopole antenna with complementary split-ring resonators

A frequency reconfigurable dual-band monopole antenna for WLAN and WiMAX applications is presented. The proposed antenna based on complementary split-ring (CSR) resonators provides single or dual frequency operation that is tunable using an integrated radio- frequency switch. The antenna is electrically small, thanks to the CSR structures, and exhibits well-behaved radiation patterns in both E- and H-planes. The antenna design, simulation, and measurement results are presented. The simulated and measured results are in good agreement. V C 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:977- 979, 2014; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.28230

Pattern and frequency reconfigurable monopole disc antenna using PIN diodes and MEMS switches

ABSTRACTDual reconfigurable microstrip disc antenna is investigated in this article starting from conventional disc. Modifications are added to produce three reconfigurable shapes. First is pattern reconfigurability by rotating the radiation pattern 60°. Second is frequency reconfigurability. Third shape is dual reconfigurability that merges between frequency and radiation pattern changes. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:187–195, 2014