Frequency Reconfigurable Double-sided Slot Antenna Using Close-coupled Biasing Technique

This paper presents the design and analysis of a reconfigurable microstrip slot antenna using RF PIN diodes as switching device for S and C band. Here pattern and frequency reconfigurable microstrip antenna is designed by changing the slot length on ground plane through six MPP4203 PIN Diodes. These six PIN diodes are used to electrically connect and disconnect the slot to alter the total slot length 76 mm in x axis and 56 mm in y axis. Here three switches are positioned in slot which is cut along the x-axis and another three switches are positioned in the slot along the y-axis. The analysis of reconfigurable antenna using PIN diode is done using the simulation performed on Ansys HFSS. The pattern and frequency reconfigurability of proposed antenna is analyzed for S (2–4 GHz) and C band (4–6 GHz) in terms of return loss and radiation pattern. The microstrip antenna design shows the pattern and frequency reconfigurability at 11 resonating frequencies. The proposed reconfigurable antenna is capable to resonate at three resonating frequencies (2.2, 2.3, and 2.4 GHz) in S band and 8 resonating frequencies (5.7, 5.8, 5.9, 6, 6.1, 6.3, 6.4, and 6.5 GHz) in C band. The simulated radiation patterns at various resonating frequencies shows pattern reconfigurability with acceptable gain in xz and yz plane of microstrip patch antenna. Furthermore the re-configurable antenna reduced the front end system's size and offers pre-filtering at the receiver. The proposed microstrip patch slot antenna is quite suited to be integrated with WLAN and Bluetooth devices with less structure complexity.

Radio Frequency (RF) plays a vital role nowadays in harvesting RF Energy from the ambient source. An antenna is required to harvest RF energy and solve the spectrum underutilization problem for the Cognitive Radio (CR) system. This paper presents an optimization of a reconfigurable Coplanar Waveguide Antenna (CPW), which harvests RF energy and is also used for sensing and communication purposes. The performance metrics of the proposed antenna are gain, radiation efficiency, front-back ratio (FBR) and group delay. First, the optimized CPW antenna (sensing antenna) is designed and fabricated in the FR4 substrate for the wideband frequency range of (0.25–3 GHz) with the fractional bandwidth percentage of 175%. The gain of the proposed optimized CPW antenna for different frequency band is: DTV band (UHF-0.47 GHz)-3.327 dBi, GSM 900-2.39 dBi, GSM 1800-3.42 dBi, 3G-3.227 dBi, and Wi-Fi-3.21 dBi. The average gain of the optimized CPW antenna for the frequency range of (0.25–3 GHz) is 3.11 dBi, and the maximum radiation efficiency of the antenna is 91.05%. Next, the optimized CPW antenna is reconfigurable, and it can be reconfigured for a specific frequency band using a PIN diode switch. When the PIN diode switch is in ON state, the antenna acts as a reconfigurable antenna (communicating antenna), and it is operated for the specific frequency band of (0.47 GHz-DTV [UHF] band), (0.9, 1.8, and 2.1 GHz-mobile bands), and (2.4 GHz-Wi-Fi bands). The maximum gain of the optimized frequency reconfigurable CPW antenna is 3.61 dBi, and the radiation efficiency is 92.5%. In the OFF state, the antenna acts as a sensing antenna, and it operates at a wideband frequency range of (0.25–3 GHz). Finally, the prototype of a four-stage Villard voltage multiplier RF-dc conversion circuit using an adjustable impedance matching network is proposed for powering the cognitive radio applications.

PurposeIn wireless communication system, use of multiple antennas for different requirements of system will increase the system complexity. However, reconfigurable antenna is maximizing the connectivity to cover different wireless services that operate different frequency range. Pattern reconfigurable antenna can improve security, avoid noise and save energy. Due to their compactness and better performance at different applications, reconfigurable antennas are very popular among the researchers. The purpose of this work, is to propose a novel design of S-shaped antenna with frequency and pattern diversity. The pattern and frequency reconfiguration are controlled via ON/OFF states of the PIN diode.Design/methodology/approachThe geometrical structure of the proposed antenna dimension is 18 × 18 × 0.787 mm3 with εr = 2.2 dielectric constant. Three S-shaped patches are connected to a ring patch through PIN diodes. The approximate circumference of ring patch is 18.84 mm and length of patch is 5 mm, so approximate length of radiating patch is 14.42 mm and effective dielectric constant is 1.93. Conductor backed coplanar waveguide (CPW) is used for feeding. The proposed antenna is designed and simulated on CST microwave studio and fabricated using photolithography process. Measurements have been done in anechoic chamber.FindingsAntenna shows the dual band operation at 2.1 and 3.4 GHz frequency. The first band remains constant at 2.1 GHz resonant frequency and 200–400 MHz impedance bandwidth. Second band is switched at seven different resonant frequencies as 3.14, 3.45, 3.46, 3.68, 3.69, 3.83 and 3.86 GHz with switching of the diodes. The −10 dB bandwidth is more than 1.4 GHz.Research limitations/implicationsPattern reconfigurability can be achieved using mechanical movement of antenna easily but it is not a reliable approach for planar antennas. Electronic switching method is used in proposed antenna. Antenna size is very small so fabrication is very crucial task. Measured results are deviated from simulation results due to fabrication error and effect of leads of diodes, connecting wires and battery.Practical implicationsThe reconfiguration of the proposed antenna is controlled via ON/OFF states of the three PIN diodes. The lower band of 2.1 GHz is fixed, while second band is switched at five different resonant frequencies as 3.27, 3.41, 3.45, 3.55 and 3.88 GHz, with switching of the PIN diodes with all state of diodes and exhibit pattern reconfigurability at 2.1 GHz frequency. At second band center frequency is significantly changed with state of diodes and at 3.4 GHz pattern is also changed with state of diodes, hence antenna exhibits frequency and pattern reconfigurability.Originality/valueA novel design of pattern and frequency reconfigurable antenna is proposed. Here, work is divided into two parts: first is frequency reconfiguration and second is radiation pattern reconfiguration. PIN diodes as switch are used to select the frequency band and reconfigure the radiation pattern. This proposed antenna design is novel dual band frequency and pattern reconfigurable antenna. It resonates at two distinct frequencies, i.e. 2.1 and 3.4 GHz, and has a pattern tilt from 0° to 355°. The conductor backed CPW feed technique is used for impedance matching.

Reconfigurable or switchable antennas are potential candidates for modern wireless and portable devices to operate at more than one frequency bands, polarizations and scanning radiation patterns in accordance with user requirements. This paper describes the design of multi-band frequency reconfigurable 7-shaped planar monopole antenna, employing 1.6 mm thicker FR4 as a substrate material and a truncated metal ground plane. The antenna operates in single as well as dual-band frequency modes depending on the state of the switch used. The proposed antenna operate in the dual frequency mode (Wi-Fi at 2.45 GHz and WLAN at 5.4 GHz) and single frequency mode (WiMAX at 3.5 GHz) when the optical switch is in ON and OFF states respectively. The bandwidths achieved are 20, 39 and 9.3% centered at 2.4, 3.5 and 5.4 GHz, frequencies respectively. The antenna is impedance matched (i.e. input impedance=51∼54 Ω) resulting in VSWR< 1.3 for the three frequency bands. Satisfactory gains of 1.92, 2.41 and 3.02 dBi and efficiencies of 86.5, 85 and 74.6% are attained at 2.45, 3.5 and 5.4 GHz frequencies respectively. Printed monopole reconfigured antennas are small, low profile and light-weight which can be used in portable electronics (mobile phones, iPads, PDAs and laptops) and wearable applications (safety and rescue operations). The antenna scattering and far-field parameters are evaluated using a numerical Finite Integration Technique (FIT) and Finite Element Method (FEM) employed in CST MWS and HFSS, respectively.

Objectives: To design new multiband antennas based on slotted rectangular patch antenna moisture sensor with comparative results to each other. The moisture sensors is compact size, easy design, low cost and have high quality responses which can be applied for determination of soil moisture measurement. A frequency reconfigurable antenna is presented with operating frequency between 2GHz to 5GHz. Methods/Statistical Analysis: A reconfigurable microstrip patch sensor is designed by using a slotted rectangular patch antenna for determination of soil moisture measurement. The length and width of the ground and patch is 30mm and 25mm as well as three slotted on the patch for accuracy. It is designed on FR-4 substrate with a relative dielectric constant 4.4 and thickness 1.6mm which is simulated by CST software as well as gets the magnitude and phase of modified design. Findings: The proposed antenna exhibits multi-frequency behavior. The modified antenna is capable for measuring the moisture between 2GHz to 5GHz. At these frequencies slotted rectangular patch antenna moisture sensor produces return loss 25dBi and capable for measure the moisture in soil with accuracy. When the resonant frequency is decreased with increase the moisture level. It will be designed for measuring the accuracy with a less time as well as triple resonant frequencies. The moisture content can be minimum and maximum at different frequencies and that can be considered for the better implementation of the approach by using the vector network analyzer. Applications/Improvements: In this paper a compact frequency reconfigurable microstrip patch antenna as a moisture sensor is presented with good return loss as well as resonant frequency for measuring the moisture in soil with accuracy as compare with the conventional one.

With the rapid development of science and technology, it is an inevitable trend for wireless communication systems to work on the same platform in different frequency bands. Reconfigurable antenna realizes the reconfiguration of parameters such as resonant frequency, polarization mode and radiation direction. The function of traditional multi-antennas can be realized by a single antenna. This paper presents a frequency reconfigurable antenna, which is especially suitable for multi-band and single-band hopping network communication systems. The simulation results show that the bias network has little effect on the antenna performance. In this paper, a polarization reconfigurable clover antenna fed by coplanar waveguide is proposed, which can realize switching function between left-handed circular polarization and right-handed circular polarization.

This article proposes a novel multifunctional wideband reconfigurable antenna with a frequency selective surface (FSS) reflector to improve gain across all operating bands. Initially, a wideband trapezoidal monopole antenna with a 138% impedance bandwidth (1.53–8.45 GHz) on a FR-4 substrate with a thickness of 0.80 mm and an area of 51 × 56 mm2 was designed. In order to achieve multifunctionality, two inverted L structures with two rectangular slots were introduced at the ground plane. Each slot functions as a filter, producing various resonating bands. To obtain the desired resonating frequency bands, the effective length of the slot was changed by strategically placing RF switching element PIN diodes. The proposed reconfigurable antenna can switch between 10 different frequency bands. To improve the gain of the proposed reconfigurable antenna, a novel FSS reflector with a 5 × 5 array of elements is placed 1.01λ (34.54 mm) below the proposed antenna. The application of the FSS results in a 3–6 dBi improvement in antenna gain, not only for the wideband range, but also for all operating frequency bands. Over the entire operating bandwidth, the radiation efficiency ranges from 93% to 75%. For GPS, RADAR, LTE42/43, WLAN, WiMAX, STM-Link, and UMTS applications, the proposed antenna operates in a wideband state, three single band states, four dual band states, and three tri band states. This work provides more antenna functionality at a lower cost, as well as significantly reduced size and space requirements. The proposed antenna can be easily integrated into portable electronic devices for a variety of wireless applications due to its broad switching capability and unique feasibility.

&lt;span lang="EN-US"&gt;In this article, a frequency reconfigurable honey-bee compact microstrip monopole antenna is proposed which is fed by a microstrip line (50 Ω) having the capability of providing dual-band as well as triple-band operation in eight distinct modes. By embedding three PIN diodes overs the honey bee arms, the effective current distribution is controlled hence resonant frequency is also changed in eight distinct modes in real-time. This is the reason the proposed antenna is portrayed as a frequency reconfigurable antenna in this paper which is suitable for cognitive radio application. This proposed antenna can be used for various wireless application such as Bluetooth, Wi-Fi, worldwide interoperability for microwave access (WiMAX), wireless local area network (WLAN), C-band, and X-band applications. The proposed antenna possesses a planner geometry of 39×34×0.87 mm&lt;sup&gt;3&lt;/sup&gt; which is printed on a substrate as flexible FR-4 (lossy) (ε&lt;sub&gt;r&lt;/sub&gt;=4.4 and tanδ=0.019). The proposed antenna exhibits voltage standing wave ratio (VSWR)&amp;lt;2 for all 19 resonant frequencies of interest and perceptible radiation pattern over entire frequency bands with a positive gain. CST microwave studio is used to find out all simulated results of antenna parameters.&lt;/span&gt;

A frequency reconfigurable patch antenna has been designed and analyzed controlled by two PIN diodes to shift among multiple frequencies. Different mode of operation has been made using computer simulation program (CST) software. A circular patch antenna has complex design calculations; thus, the proposed antenna offered a reduction in complexity using an uncomplicated structure. Tow active switching elements have been used to reconfigure the proposed antenna design to operate in multiple bands by shifting between ON and OFF states. Extensive investigation has been made by varying the resistance, inductance, and capacitance components of the selected PIN diodes. A compact size structure of 31.16 mm x 27.04 mm x 1.6 mm functions in the C-band at 4.7 GHz, X-band at 9.2 GHz, Ku-band at 13.3 GHz, and 17 GHz, and K-band at 18.7 GHz when both PIN diodes are OFF state. When the first PIN diode is ON and the second is OFF, it functions in the X- band at 8.7 GHz, Ku-band at 13.1 GHz and 15.9 GHz, and K-band at 18.7 GHz. Then, when the first PIN diode is OFF and the second PIN diode is ON, it functions in the C- band at 5.4GHz, X- band at 9.4 GHz, Ku- band at 13.6 GHz and 17.1 GHz, and K- band at 18.7 GHz. Finally, when both PIN diodes are ON state, it functions in the Ku- band at 12 GHz and 15.8 GHz, and K- band at 18.7 GHz. The proposed reconfigurable circular patch antenna presented a compact unfussy size, cheap, and meek to implement to operate in current communication systems such as satellite communications (space operation, earth exploration, earth-to-space, space-to-earth, satellite TV Broadcasting, and fixed satellite services (FSS)), Mobile communication long-term evolution (LTE band 46), Mobile communication 5G sub-6GHz, Wireless-Fidelity 7 and Radio implant medical devices (IMD).

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 εr = 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.

This paper proposes frequency reconfigurable antenna for outdoor wireless communication systems, the 4 x 4 array antenna has designed at two resonant frequencies 7.5 GHz and 8.85 GHz. The periodic dumbbell geometry etched on the ground layer newly proposed with dual functionality, to control desired frequency and to couple radiating patches at the top substrate with feeding line at the bottom substrate. The reconfigurability of the patch antenna is controlled by utilizing the copper pad of the feeding network with OPEN and SHORT states. The reconfigurable antenna has been simulated and optimized using Computer Simulation Technology (CST) to get the desired responds. The good agreement between simulation and measured results indicates that the frequency reconfigurable patch array antenna using Periodic Dumbbell Slotted Aperture Structure (FRPDSA) is feasible to support outdoor wireless communication systems.

Reconfigurable antennas provide solution where multiple types of wireless network are used for different application. The basic advantage of reconfigurable antennas is that they can alter the antenna parameter based on required field of operation. A common technique to design a reconfigurable antenna includes a microstrip patch antenna which is integrated with switching circuit. Here, a new design approach for frequency reconfigurable antenna is introduced for possible satellite applications. The proposed antenna consists of a radiating rectangular patch with defected ground plane. Reconfigurability can be achieved by using PIN diode switches. In the OFF state, the antenna acts as a wide single band configuration (3.6–4.2 GHz) with resonant frequency at 3.99 GHz. While in ON state, the antenna works as dual band configuration (3.3–3.5 GHz and 4.4–4.8 GHz) with resonant frequencies at 3.4 GHz and 4.6 GHz. The antenna is simulated by using CST microwave studio.

In this paper, a new compact design of frequency reconfigurable slot antenna is presented. The proposed radiating patch consists of two symmetrical D shape slots and incorporates four PIN diodes with two stubs which cover a small dimension area of 8.6 × 6.0 × 1.6 mm3. The ground plane is modified by etching two parallel rectangular slots to enhance the bandwidth and design parameter of the antenna. RF pin diodes are used as a switching mode in the slotted D section of the patch which affects the electrical length of the slot antenna, therefore switchable frequency response is obtained. The antenna produces four dual-band states and twelve triple-band states among the sixteen states of diode configuration. The designed antenna resonates at six different resonating frequencies such as 17.4 GHz, 17.5 GHz, 18.9 GHz, 19.0 GHz, 24.9 GHz, and 25 GHz and covers the wide range of frequency from 17.2 to 25.5 GHz which makes it applicable to function at the Ku and K band applications. Simulation of an antenna is done by Ansys HFSS 17.0 software. The results of the simulation show that the antenna has achieved a stable radiation pattern with an appreciable gain of 10 dB, peak directivity 4.26 dBi, peak gain 5.66 dBi, and a maximum bandwidth of 1 GHz with 98% radiation efficiency at these operating frequency bands.

With the constant increase in communication requirements in modern society, the number and type of antennas on communication platforms have been increasing at an accelerating rate. This has led to a continuous increase in platform volume and weight, and the electromagnetic environment of antenna operating has increasingly worsened, seriously restricting the further development of communication systems. As a new communication system antenna type, a reconfigurable microstrip antenna can reconstruct operating frequencies, beam directions, etc., by changing the antenna structure to provide the good multifunction characteristics of a single antenna, avoiding the electromagnetic compatibility issues caused by numerous system antennas. At present, most of the research on reconfigurable antennas judges the influence of structural characteristics on electromagnetic characteristics by simulation, which has imposed restrictions on their development and application. Therefore, a reconfigurable antenna with a resonant frequency of 8.66 GHz and 15.26 GHz and a reconfigurable antenna with maximum radiation directions of 36.2° and −36.5° are designed in this paper, and the electromechanical coupling theory of the reconfigurable antennas is studied. The resonance frequency coupling model and the pattern function coupling model considering the structural deformation of a reconfigurable microstrip antenna are established. Within the applicable range of antenna structural parameters, the relative error between the resonance frequency coupling model and the pattern function coupling model is less than 5%, which meets practical engineering application requirements. Finally, the method is shown by experimentation to verify the accuracy and validity of the proposed electromechanical coupling model.

본 논문에서는 상용 초고주파 MEMS 스위치를 이용하여 세 개의 주파수 대역에서 재구성 동작이 가능한 주파수 재구성 능동 배열 안테나 시스템(Reconfigurable Active Array Antenna System: RAA System)을 제안하였다. MEMS 스위치는 삽입 손실 및 선형성 특성이 우수하고 격리도가 높아 주파수 재구성 시스템 구현 시, 재구성을 위한 스위치로 인한 성능 열화가 거의 없다는 장점이 있다. 제안된 주파수 재구성 능동 배열 안테나 시스템은 간단한 구조의 임피던스 매칭 회로(Reconfigurable impedance Matching Circuit: RMC)를 갖는 주파수 재구성 증폭기(Reconfigurable Front-end Amplifier: RFA)가 집적화 되어 있으며, 안테나 방사체(Reconfigurable Antenna Element: RAE)와 재구성 제어 보드(Reconfiguration Control Board: RCB)로 구성되어 있다. 본 논문에서 제안한 RAA 시스템은 850 MHz, 1.9 GHz, 3.4 GHz의 세 개 주파수로 재구성되어 동작하며, 안테나 방사체는 <TEX>$2{\times}2$</TEX> 배열을 가지고 각각의 방사체는 광대역 다이폴 형태를 갖는다. 제작된 RAA 시스템은 실험을 통하여 그 타당성을 확인하였다. In this paper, a novel frequency reconfigurable active array antenna(RAA) system, which can be reconfigurable for three reconfigurable frequency bands, is proposed by using commercial RF MEMS switches. The MEMS switch shows excellent insertion loss, linearity, as well as isolation. So, the system performance degradation of the reconfigurable system by using MEMS switches can be minimized. The proposed frequency reconfigurable active antenna system is consisted with the noble frequency reconfigurable front-end amplifiers(RFA) with the simple reconfigurable impedance matching circuits(RMC), reconfigurable antenna elements(RAE), as well as a reconfiguration control board(RCB) for MEMS switch control. The proposed RAA system can be reconfigurable for three frequency bands, 850 MHz, 1.9 GHz, and 3.4 GHz, with <TEX>$2{\times}2$</TEX> array of the RAE having broadband printed dipole antenna topology. The validity of the proposed RFA as well as RAA is also presented with the experimental results of the fabricated systems.