Separated Microstrip Antenna for Satellite Simulators

Microstrip patch antenna have been designed for satellite simulator system for transceiver antenna. The transmitter antenna is designed for the uplink at 14.25 GHz and receiver antenna is designed for the downlink at 11.45 GHz. The transmitter and receiver antennas are designed on a single substrate with microstrip transmission feedline on two sides for each frequency band. Quarter-wavelength structure is used for matching. Simulation results reveal a broadband structure for reflection, with a gain of 7 dB and high efficiency

2 x 2 Phased Array Consisting of Square Loop Antennas for High Gain Wide Angle Scanning With Low Grating Lobes

A 2 × 2 array antenna comprised of conventional hybrid high impedance surface-based reconfigurable square loop antennas (SLAs) as elements is presented. The SLA element has four conducting arms and each arm is fed at the middle by vertical probes, which is connected to a 50 Ω port at the bottom of antenna ground plane. Thus, the SLA element has four feeding ports and it is capable of generating five distinct radiation patterns by using a combination of its feeding ports. Depending upon which of its four ports are excited it can provide four high gain off-boresight tilted beams (8.9 dBi at θmax= 36°) in four different quadrants of the space (tilted beam mode). When all the four ports are simultaneously excited with phases of 0°, 0°, 180°, and 180°, it provides an axial beam (6.5 dBi) at boresight (axial beam mode). By combining these two modes the 2 × 2 array of SLAs can provide a scanning range of-60° to +60° in the elevation plane with high-gain beams (14-11.2 dBi)

MMW 60 GHz Tunable Periodic Filter

A novel mm-wave periodic filter structure has been proposed based on a new design approach. The filter performs at 60 GHz with 3.5 GHz bandwidth. The structure composed of periodic Microstrip stubs on BL037 Liquid Crystal substrate. Changing the bias voltage of LC provides a tunability from 58.5 to 62 GHz, while maintains the fractional bandwidth around 5%. The return loss of passband is better than 10dB with insertion loss variation from 3.8 to 5 dB. In addition, the effect of a different LC substrate (i.e. GT3-23001) has been investigated which provides similar behavior with a wider tuning distance

EBG enhanced broadband dual antenna configuration for passive self-interference suppression in full-duplex communications

A full-duplex system is realised using dual EBG isolated rectangular spiral antennas and its performance is compared with the same full-duplex system using a circulator and a single spiral antenna element. The new antenna system consists of two antennas one with RHCP and the another one with LHCP implemented on a single substrate. Two columns of EBG is placed between the two antennas to improve the isolation. At the operating frequency of 3.2 GHz, the antenna configuration has nearly 31 dB isolation. For the identical baseband input power, the full-duplex system utilising dual spiral antenna configuration exhibits 9 dB higher isolation than the circulator based full-duplex system

Novel Interference Suppression Null Steering Antenna System for High Precision Positioning

The high precision (centimetre accuracy) positioning systems are set to play a key role in revolutionising smart farming, self-driving cars, drone deliveries, heavy machine navigation, etc. With so much at stake the technology also needs protection from an intentional sabotage or denial of service. It is very easy with current satellite-based navigation jammers to disrupt a navigation service. Our proposed technology solves this challenge in a compact and cost-effective way. Compared to normal navigation patch antennas our proposed dual ring antenna offers over 30 dB of protection. Thus, if a patch antenna-based navigation system is disturbed at 1 watt of interference power, it will take 1000 watts to disrupt navigation system working on our proposed system. With the size of only 130 mm ×130 mm and cheap large-scale manufacturing, our proposed antenna is perfectly suitable for applications for safety and prosperity of the smart nation-based living

Effective dielectric constant of top grounded coplanar waveguide on liquid crystal superstrate

AbstractThe effective dielectric constant of the top grounded coplanar waveguide with a liquid crystal (LC) superstrate for phase shifting applications is investigated in the frequency range of 30–60 GHz. Two nematic LC mixtures, namely E7 and MDA‐00‐3506, are used as the superstrate. The measurements show that MDA‐00‐3506 offers higher values of phase shift per millimeter than its E7 counterpart. In particular, the MDA‐00‐3506 provides 3.14°/mm, whereas E7 gives 2.79°/mm at 60 GHz. The results of the dielectric constants from measurement and computer modeling are found to agree to within 5%. For the modeling, a comprehensive finite element package predicting the local alignment of LC molecules and effective dielectric constant at different bias voltages and frequencies are used. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1416–1418, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27564</jats:p

Dual-beam orthogonal circular polarized antenna

© 2019 European Association on Antennas and Propagation. A novel mm-wave-antenna structure has been proposed and investigated. It operates at 32 GHz with 3.2 GHz (-10 dB) bandwidth. It has the potential to be easily scaled for 5G band. The structure is composed of a monopole antenna above a ground plane and an SIW wall. The antenna structure was studied numerically, revealing a directivity of 6.5 dBi within a bandwidth of 3.2GHz. In addition, the effects of different structural parameters have been investigated. The radiation pattern of the antenna reveals two orthogonal beams, circularly polarized, separately in the left and right direction

Microstrip Device for Broadband (15–65 GHz) Measurement of Dielectric Properties of Nematic Liquid Crystals

The essential dielectric properties, the basic alignment techniques, and the common measurement methods of the nematic liquid crystal (LC) at RF are briefly reviewed. A new device for the broadband measurement of the dielectric constants and loss tangents of nematic LCs at microwave and millimeter-wave frequencies is presented. This device whose specification and fabrication are outlined is essentially a two dielectric layer microstrip structure with coplanar-waveguide terminals, which is easy to fabricate. Compared to previous structures, the proposed device is extremely broadband with 15-65-GHz bandwidth, benefits from a solid exposed ground plane for easy temperature test, and operates under bias voltage. The technique for the extraction of the dielectric parameters of the nematic LC analyzed by this device is explained and the sources imposing the frequency limits on the device performance are identified. Two different nematic LCs, MDA-00-3506 and GT3-23001, are characterized and the results are shown to compare well with those available in the literature. In the comparisons, the maximum difference found for the dielectric constants for MDA-00-3506 is 5% and for GT3-23001 is 5.3%

Dual-Band Low-Profile Capacitively Coupled Beam-Steerable Square-Loop Antenna

In this paper, a dual-band low-profile switched beam square-loop antenna (SLA) fed by capacitively coupled feeding mechanism is presented. Two square loops are excited by four rectangular feeding patches which are fed with vertical probes. The capacitively coupled feeding arrangement introduces capacitance into the antenna input impedance and cancels the high inductance due to close proximity of ground plane and feeding probes. This feeding technique enables the antenna to be matched to 50 Ω feedline and helps in the realization of low-profile SLA. The antenna has a height of 3.04 mm; i.e., λ0 /26 for the operating frequency of 3.8 GHz. The dual-band capacitively coupled square-loop antenna (DBCCSLA) is developed for covering 3.8- and 4.7-GHz frequency bands, and each band possesses an impedance bandwidth of 120 MHz. In both frequency bands, when any of the four ports is excited, keeping other ports open circuited, the antenna generates a tilted beam directed away from the excited port, having a maximum directivity of 9.3 dBi. By exciting ports one at a time, the antenna can steer its tilted beam in four different quadrants to scan the entire space in front of the antenna

A Circularly Polarized Low-Cost Flat Panel Antenna Array With a High Impedance Surface Meta-Substrate for Satellite On-the-Move Medical IoT Applications

A 1×3 linear antenna array consisting of Quad-Arm Curl antenna with a High impedance meta-surface (QACH) is presented. We believe that it is the first linear phased array solution which can provide 360° azimuth coverage. This array has been designed to operate at L-Band (1.518 - 1.675 GHz) and generate right hand circularly polarized radiation to primarily target the Inmarsat BGAN satellite constellation. The metamaterial structure integrated into each antenna element allows a low-profile height of 17.2 mm (λ1.597/10.9). Since the curl element has wideband characteristics, the array is able to provide shared aperture functionality. The array guarantees high gain beam steering for low elevation angles (up to θ = 70° from the zenith) with an average gain of 7.96 dBic at θ = 70°. In comparison, to achieve an equivalent high gain a conventional 4×5 patch array would be required (3 elements vs 20 elements). This means that the proposed array requires 80% fewer phase shifters, amplifiers and LNAs. This translates to a crucial commercial advantage in relation to manufacturing cost. This development can lead to disruption of the existing Satcom market by lowering the barrier-to-entry for customers looking for a mass deployable, low-cost IoT on Satcom solution