External parasitic loaded pin diode integrated multiband frequency reconfigurable antenna

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.

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.

ASYMMETRICALLY SLOTTED, TUNABLE AND SINGLE MODE CIRCULARLY POLARISED MICROSTRIP ANTENNA FOR IoT APPLICATION

<span lang="EN-US">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<sup>3</sup> which is printed on a substrate as flexible FR-4 (lossy) (ε<sub>r</sub>=4.4 and tanδ=0.019). The proposed antenna exhibits voltage standing wave ratio (VSWR)<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.</span>

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.

The major focus of the paper is on frequency reconfigurable antenna loaded with slots and slit for future wireless applications. The proposed microstrip antenna with slot, slits and defected ground structure loaded with PIN diode provides a compact and versatile solution with acceptable results for S11< – 10 dB, VSWR ~ 1, and Bandwidth 17.07%. A multi-band frequency operation is observed for 3.76 GHz, 4.26 GHz, 8.06 GHz, 10 GHz, 11.5 GHz and 12 GHz frequencies. The results demonstrate that the antenna bandwidth is a combination of narrowband and broadband, thereby making the antenna a suitable candidate for cognitive radio application for both functionalities i.e. sensing and communicating. The bandwidth observations range from 2.6%, 7.98%, 4.7%,11.3%, 8.78%, 17.073%, i.e. we can say the bandwidth is configurable. The designed antenna is proposed for applications like Cognitive radio, UWB applications, Microwave communication (S, C and X).

In this paper, a novel frequency reconfigurable coupling microstrip patch antenna is presented. A coplanar waveguide (CPW) feed line integrated on the ground plane is adopted in the structure to provide $\text{TM}_{21}$ mode. Four PIN diodes are mounted on the patch gap to achieve frequency reconfiguration. By controlling the on-off state of PIN diodes electronically, resonant frequency points (5.75,5.84, and 6.06 GHz) can be adjusted. What's more, a wide tunable range is achieved by loading more parasitic patch.

This paper presents the design of a rectangular patch antenna with compound reconfigurability in terms of operating frequency and radiation pattern using only four PIN diodes. Two PIN diodes namely, PD1 and PD2, are implanted on a rectangular slot of the driven patch for frequency reconfiguration. While other two PIN diodes PD3 and PD4, are uniquely arranged with shorting posts between parasitic elements and ground, perform the pattern reconfiguration operation. Switching of PD1 and PD2 changes the effective electrical length of driven patch for four different measured resonant frequencies at 3.35, 4.02, 4.12 and 5.12 GHz. Moreover, ON/OFF states of PD3 and PD4 alter the function of parasitic elements between director and reflector to achieve H-plane pattern reconfiguration in all reconfigurable operating frequencies. Measured tilt angles at 3.35, 4.02, 4.12 and 5.12 GHz bands are (−40°, 0°) (+30°, −42°, 0°) (+40°, −40°, 0°) and (+36°, −43°) respectively. Measured results of reflection coefficient and radiation pattern are in good agreement with the simulated results, which validates the frequency and pattern reconfigurable performances of the antenna. The proposed antenna can be used for various C band wireless applications such as sub-6-GHz 5G (3.3 GHz, 4 GHz), and WLAN (5.2 GHz).

The antenna's design and frequency reconfiguration have a significant impact on its performance, which makes it perfect for a particular use case such as the Internet of Things. In this, study developed a unique metamaterial patch antenna design using a frequency reconfiguration technique. In the study, the metamaterial microstrip patch antenna (MMPA) was deployed in an Internet of Things application utilizing a frequency reconfiguration approach, achieved with the help of a PIN Diode. Changing the bias of two PIN diode switches altered the resonating frequency. An FR-4 substrate with a copper patch forms the proposed antenna. The suggested antenna construction has dimensions of 23 x 19 〖mm〗^2. Two steps are involved in the design of a reconfigurable multiband antenna. The first designed Monopole for a Single Band with a centre frequency of 4.0GHz and the Second designed Multiband using a Rectangular Split Ring Resonator (RSRR) on the Ground Plane which includes two PIN diodes as switches, is evaluated in the ON-ON, OFF-ON, ON-OFF, and OFF-OFF switching scenarios. Antenna performance parameters like Gain, reflection coefficient, radiation efficiency, and standing wave ratio of voltage are used to estimate the presentation of the suggested antenna. At the Operating frequency of 3.6 GHz, the suggested antenna's efficiency and gain are 1.68 dB and 81%, respectively.

In this study, a frequency reconfigurable dielectric resonator antenna (DRA) metallic strip coupled operating in the IEEE 802.11a is presented. The resonating element is composed of a single rectangular dielectric resonator (RDR) excited by three metallic strips pasted on the RDR front side. To achieve frequency reconfigurability, the RDR is excited by either one, two or three metallic strips. The exciting metallic strips are connected to a three fork microstrip network that is integrated with two PIN diodes. The frequency reconfigurability is obtained by switching from both PIN diodes are OFF state to both are ON state. The obtained -10 dB for OFF-OFF state, ON-OFF state and ON-ON state were 5.8024 GHz, 5.604 GHz and 5.58 GHz, respectively. The 30 × 25 mm2 findings makes it a good candidate for applications operating within the IEEE 802.11a band.

Sensors such as phased array radars play a crucial role in public safety. They are unavoidable for surveillance, threat identification and post-disaster management. However, different scenarios impose immensely diverse requirements for these systems. Phased array systems occupy a large space. In addition, if different antenna systems are needed for each function, the space required can be considerably large. For transportable platforms, such as ships and aircrafts, space and weight are critical parameters. Therefore, reconfigurable multi-band antennas are very attractive solutions for future multi-function sensor systems. Within this research work three different approaches are investigated to realize antennas for reconfigurable phased arrays. Wideband antenna designs constitute the first approach. Integrating this type of antennas with frequency selective filters provide the opportunity for fine tuning within one radar band. The wideband operation of the antenna is achieved by the blind-via feeding section and the quasi electric-magnetic radiating structure. The second approach involves the design of an antenna element with p-I-n diode switches. The switches are used to alter the antenna structure and thereby the operating frequency. Measured results verified the frequency reconfigurable capability of the antenna within L/S radar bands with frequency ratio more than 2:1. The planar structure, the back feeding mechanism, the compact size and the simple bias network made the proposed antenna suitable for array applications. The large frequency ratio and its usability in phased array applications made the design novel. Furthermore, for these frequency reconfigurable elements, a unique multi-scale array structure is introduced which can assure wide angle scanning for both frequency bands. The advantage of this novel array configuration is twofold: reduce the mutual couplings in the lower band, and increase the scanning volume for the higher band. A planar array demonstrator validated the proposed concept. In the third approach the operational band of an antenna is tuned by variable-impedance matching. In this study, the standard 50 ? matching is avoided and many advantages of variable-impedance matching are demonstrated. First, the principle is verified by tuning the frequency band of a microstrip antenna by an input-impedance tuneable CMOS RF-frontend. In the second design a novel dual-band E-slot antenna, with 2.5:1 frequency ratio, was designed. By changing the input-impedance the operating frequency of the antenna can be switched from L- to S-band. Variable-impedance matching provides few other advantages to phased array antennas. A scan-angle dependent impedance matching will assure low reflection coefficients for the entire scanning volume. On the other hand, it will reduce interfering and jamming signals coming from adjacent angles. The outcomes of this research work have led to solid understanding of how we can realize frequency reconfigurable antennas for adaptive phased arrays. The results will be particularly valuable in developing future narrow or wide beam radar systems with frequency reconfiguration and angular filtering capabilities.

This paper presents a reconfigurable antenna operating in three modes at different frequency bands with pattern reconfiguration. Frequency and pattern reconfigurability are achieved using four PIN diodes. In particular, two diodes are mounted in the radiating part of the hexagon shape to perform the frequency reconfiguration of the antenna. The other two PIN diodes are connected with the inverted L‐shaped and CPW ground by changing the main lobe beam steering to achieve the pattern reconfiguration. An antenna has been designed, fabricated, and numerically and experimentally assessed. The prototype of the antenna is fabricated on a commercially available FR‐4 substrate of thickness 1.6 mm (εr = 4.3). Thus, the proposed antenna supports several 5G sub‐6 GHz bands (3.1 GHz, 4.1 GHz, and 3.8 GHz), WiFi (2.45 GHz), as well as (7.8 GHz, 9.5 GHz) X‐Band Satellite applications. The obtained results are quite promising. In particular, it is observed that the measured results are in close agreement with the simulation results, and the proposed (compact) antenna prototype can be a prospective candidate for future portable devices, sensor networks, and telecommunication applications.

ABSTRACTIn this letter, a novel frequency reconfigurable antenna with the aid of liquid metal is presented. The proposed antenna incorporates a 3D‐printed fluidic channel, which is placed cross to the metallized part of radiator. Compared to general meandered channels, the proposed cross placed fluidic channel ensures less liquid metal to be consumed, whilst it achieves the same capability of frequency reconfiguration as a solid patch. More importantly, it allows the proposed antenna to have a promised total efficiency thorough its switchable frequencies. The proposed antenna can switch among 2.1, 2.6, 4.4, and 11 GHz, enabling it to be adopted in various applications.

A miniaturized wideband and multi-band on-demand reconfigurable antenna for compact and portable devices

In this paper, we propose a compact frequency reconfigurable (FR) multiple-inputmultiple-output (MIMO) antenna in a overall size of 51 × 53 × 0.8 mms. The MIMO antenna consists of two symmetrical FR ones using two PIN diodes on ground plane and has a simple bias circuit without capacitor. By switching the PIN diodes, the FR MIMO antenna can operates in the three states covering bands of tte universal mobile telecommunication system (UMTS), of the long-term-evolution (LTE) at 2.3 GHz, and 2.6 GHz with peak gains of 1.55, 1.81, and 0.87 dBi, respectively. A slot is added on the ground plane to achieve a low mutual coupling between antenna elements of less than −20 dB in all operating bands. The process of antenna design as well as calculating desired frequency bands are presented in detail. The antenna is fabricated on FR4 substrate and the simulated S-parameter results of the antenna are in good agreement with measurement results.