Graphene‐based multimode inspired frequency reconfigurable user terminal antenna for satellite communication

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 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.

This communication proffers a graphene based microstrip reconfigurable antenna capable of switching between two frequency bands (S-band 3.03 GHz and C-band 5.17 GHz and 6.13 GHz). A graphene nanoparticle based conductive ink is printed on the cotton showing surface resistance of 2.7 Sq. −1, conductivity of 0.37× 105 Sm−1. An excellent radiation efficiency of above 55% is achieved at the dominant mode (TM 10 , 3.03 GHz. The frequency reconfigurability is introduced by exciting the higher order modes, TM 02 and TM 20 through two different feeding locations and an external RF Switch.

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

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 circularly polarized (CP) and frequency reconfigurable microstrip antenna with loading inductive is presented in this paper. The designed antenna is comprised of a radiating patch, four short-circuited grounded metal posts, and four coupling branches. Each coupling branch has an end that is coupled to the shorted ground post and is also connected to the parasitic branches by means of a group of PIN diodes. By controlling the state of the PIN diodes connected to each parasitic branch, the working resonant frequency of the antenna can be changed. In order to further understand the mechanisms of operation of the antenna, the equivalent circuit model was built, and the circuit model of the antenna was analyzed, and this analysis was used for the development of the frequency reconfigurable microstrip patch antenna. Furthermore, the parameters of specific equivalent circuits can be solved by the three lengths of branch. Meanwhile, the calculated results derived from the given resonant frequency formula for the antenna are in good agreement with the simulation results of the antenna. Simulated results for the input impedance of the antenna are also in good agreement with the calculated values for the equivalent circuit. Finally, the antenna is fabricated and measured, and the measured results show that the antenna can not only achieve frequency reconfiguration at 1.14 GHz, 1.21 GHz, and 1.39 GHz but also accord well with the simulation value, while maintaining a compact size.

A triangular patch frequency reconfigurable an-tenna is designed for wireless and UWB applications. Frequency reconfigurability is achieved by inserting PIN diodes between the radiating patch and the three parasitic stubs. The gained frequencies at 2.1 – 2.6 GHz and 2.7 – 7.3 GHz are propagated by incorporating patches around the radiating patch and placing the diodes in between the PIN patches. The multi-band operation is accomplished using the parasitic patches and PIN diodes. The designed antenna can strain the frequency from ultra-wideband to multi-band. Gain and Radiation Efficiency are improved in the perspective design. Along with the wireless applications, the designed antenna is covering the lower frequencies of C- band. Co and cross polarizations are refined in both E and H plane.

This paper proposes a novel wideband to concurrent tri-band frequency reconfigurable microstrip antenna. The frequency reconfiguration is achieved by using a pair of PIN diodes in the antenna feed line to switch the antenna either in wideband mode or in concurrent tri-band mode. In order to improve the bandwidth and gain of the antenna for wideband operation, the properties of J-K inverter and split ring resonators are exploited. To demonstrate the versatility of this concept a prototype is fabricated and tested here. The tested results in wideband mode shows that the proposed antenna operates from 3.58 to –3.82 GHz, which is 4.08 times larger than the bandwidth of a simple microstrip patch antenna. In the concurrent tri-band mode frequency tuning is done by microstrip open stub at 1.5 GHz, 1.9 GHz, and 3.5 GHz. Gain of the proposed antenna is better than 2.7 dB in wideband mode and 2.7 dB in concurrent tri-band mode.

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.

The authors map the differences between various reconfigurable antennas and present a payoff metric for each type. They evaluate three distinct schemes of reconfiguration: pattern, frequency, and polarisation. They show that the often neglected losses play a pivotal role in the effectiveness of reconfigurable systems. For each of the pattern, polarisation and frequency reconfigurable antennas, they define a quantity that reflects the number of non‐overlapping radiation patterns, orthogonality of the polarisation states, and the covered fractional bandwidth, respectively. Then, these quantities are divided by the amount of added losses. Thus, these metrics capture both the increased diversity due to the reconfiguration states and the associated losses. Moreover, the relationship between these metrics and the capacity of a communication system is discussed. Finally, application of the payoff metrics is demonstrated by comparing several reconfigurable antenna architectures from the literature. They show that established payoff metrics can be successfully used to evaluate and quantify the merits of reconfigurable antennas by using only antenna parameters rather than going through system‐level analysis.

Planar Beam-forming Antenna Array for 60-GHz Broadband Communication

Analysis of frequency reconfigurable microstrip patch antenna with unidirectional radiation pattern for IRNSS band

A novel concept of a dual-sense circularly polarized dielectric resonator antenna (DRA) for the Global Navigation Satellite Systems (GNSS) and other satellite communications is presented. The concept introduces a loaded annular dielectric resonator excited using four vertical conformal strips fed in a quadrature. The most unique feature of this antenna is the resonator load, which modifies the boundary conditions of the resonator core. The load is a one-dimensional array of periodic elements that behave like an electromagnetic band-gap structure (EBG). The impact on the antenna performance is multifold, including improved bandwidth, radiation efficiency and reduced mutual coupling between the excitation ports. The experimental results show that this antenna effectively covers both the lower (1165-1300 MHz) and upper (1560-1610 MHz) GNSS bands. The 0 dBic gain and 3 dB axial ratio (AR) bandwidth significantly exceed the 10 dB return loss (RL) bandwidth. The 0 dBic gain and 3 dB AR beamwidth range from 105° to 120° and from 135° to 165°, respectively, within the GNSS bands. The antenna also exhibits a stop-band at 1355 MHz.

In recent times, there is a extensive demand for wireless systems that can provide multiple access over a wide spectrum and use of electromagnetic spectrum efficiently. But the conventional antenna does not meet the demand of modern day wireless communication systems. So single radiating element called reconfigurable antenna is designed which has a capability to switch its characteristics in real time condition. Reconfigurable antennas are classified as frequency, radiation pattern and polarization reconfigurable antenna according to its switching behavior of antenna. The main goal of this paper is to review various worldwide articles pertaining to the frequency reconfiguration patch antennas, that has extensively reduced the complexity in structure and thereby the antenna size.

Frequency reconfigurable antenna actuated by three-storey tower kirigami