Hybrid graphene–copper UWB array sensor for brain tumor detection via scattering parameters in microwave detection system

Hybrid graphene–copper ultra-wideband array sensor applied to microwave imaging technique is successfully used in detecting and visualizing tumor inside human brain. The sensor made of graphene coated film for the patch while copper for both the transmission line and parasitic element. The hybrid sensor performance is better than fully copper sensor. Hybrid sensor recorded wider bandwidth of 2.0–10.1 GHz compared with fully copper sensor operated from 2.5 to 10.1 GHz. Higher gain of 3.8–8.5 dB is presented by hybrid sensor, while fully copper sensor stated lower gain ranging from 2.6 to 6.7 dB. Both sensors recorded excellent total efficiency averaged at 97 and 94%, respectively. The sensor used for both transmits equivalent signal and receives backscattering signal from stratified human head model in detecting tumor. Difference in the data of the scattering parameters recorded from the head model with presence and absence of tumor is used as the main data to be further processed in confocal microwave imaging algorithm in generating image. MATLAB software is utilized to analyze S-parameter signals obtained from measurement. Tumor presence is indicated by lower S-parameter values compared to higher values recorded by tumor absence

Bandwidth and gain enhancement of a circular microstrip antenna using a DNG split ring resonator radome

This paper present the design of a circular patch microstrip antenna with enhancement in terms of bandwidth and gain using a dielectric double negative (DNG) split ring metamaterial radome. This radome is positioned on top of the CP antenna operating from 5.2 GHz to 6.4 GHz. The metamaterial radome comprises of two alternate split rings of negative permittivity, permeability and refractive index. The circular microstrip antenna bandwidth of 430 MHz has been realized by the presence of DNG metamaterial radome compared to 220 MHz without the radome. The gain has been increased as well from 1.84 dBi to 3.87 dBi

Low insertion loss of surface mount device low pass filter at 700 MHz

The paper involved with the design, simulation and fabrication of 6th order elliptical-based Surface Mount Device (SMD) LPF with cutoff frequency at 700 MHz. Fabricated LPF is consisted of four PCB layers which components of SMD are soldered on the top layer. Another three layers is for grounding and shielding, power supply and grounding void. The four layers is crucial to avoid interference between components. The research has find out that the momentum simulation is definitely required to improve the signals response compared to a normal simulation by ADS software. The comparison between momentum simulated versus measured and normal simulated versus measured is 0.2 dB and 29 dB correspondingly. Such huge difference leads to conclusion that momentum simulation is saving time without having much struggles and efforts to get optimum readings. The Proposed SMD LPF has a very low insertion loss of 0.965dB with a transition region of 195 MHz which is good steepness to avoid any image frequency

Gain enhancement of microstrip patch antenna using artificial magnetic conductor

The paper presents an artificial magnetic conductor (AMC) structure to enhance the gain of the double microstrip patch antenna. By placing this kind of metamaterial in between the two Rogers RT5880 substrates, the antenna achieved lots of improvement especially in terms of size miniaturization, bandwidth, return loss, gain and efficiency. The antenna is intended to operate at 16 GHz where the prospect fifth generation (5G) spectrum might be located. Integration of AMC structure into the proposed antenna helps to improve nearly 16.3% of gain and almost 23.6% of size reduction

A multi band mini printed omni directional antenna with v-shaped for RFID applications

This paper presents a mini multi-band printed omni-directional antenna with v-shaped structure for radio frequency identification (RFID) applications. The proposed multi-band antenna is developed from the initial v-shaped design which is only capable of working as a single-band antenna. By deploying a concept of dipole antenna to an initial design, the proposed antenna is accomplished to operate with two different modes of RFID system which are passive and active modes at frequencies of 915MHz and 2.45 GHz respectively. The passive RFID tag is invented when a chip of Ultra High Frequency (UHF) is integrated with a proposed multi-band antenna. This passive tag, which is able to radiate with the measured signal strength, shows that the reading ranges are boosted almost two times compared to the conventional inlay antenna. The maximum reading range of passive RFID tag with inlay antenna is 5 m, though a reading range up to 10m is achievable through the deployment of the proposed antenna at a measurement field. Implicitly, the measurements carried out on the antenna are in good agreement with the simulated values. Moreover, the size of the mobile passive RFID tag has been substantially as 100mm × 70 mm, even though the antenna is fabricated with an inexpensive FR-4 substrate material. With the reasonable gain, coupled with cheaper material and smaller size, the proposed antenna has attractive potentials for use in RFID applications with multiple frequency antenna for active and passive tags

A compact RLSA antenna with polyproplyene composite

The research presents the effects of using polypropylene (PP) configuration on the novel radial line slot array (RLSA) antenna. The combination of PP with FR-4 could be affect the value of dielectric permittivity itself. Polypropylene leads the proposed antenna in achieving high gain performance of 40% higher than air gap antenna and 60% over than conventional RLSA antenna. Parametric study has been done towards achieving the optimum antenna performance such as return loss, gain, half-power beamwidth (HPBW), and bandwidth. This proposed novel antenna is capable of shaping its radiated beam in terms of half-power beamwidth (HPBW) and gain up to 45.3° and 10.52 dB (˜ 11 dB) respectively with ability to operate within the frequency range 5.4953 GHz to 5.894 GHz. With all capabilities mentioned, the antenna is highly potential to be deployed for point to point application

Beam‐reconfigurable crescent array antenna with AMC plane

A beam‐reconfigurable crescent array antenna with AMC plane is presented for application at 9.41 GHz. The unit cell of the AMC plane is modeled based on a square patch integrated with rectangular ring slot with mirrored C‐shaped structures, placed between two layers of Taconic TLY‐5 substrate and located near to the main radiating element. The presented AMC design is achieved an operating bandwidth of 2.82 GHz (30%) with a center frequency of 9.41 GHz. It is found that the AMC plane can reduce the thickness of the structure in comparison to the use of a conventional ground plane, which leads to the overall compactness size of the proposed antenna of 1.1λ × 2.57λ. Moreover, through the implementation of 12 × 4 AMC unit cell, the proposed antenna improved its performance with a maximum gain and total efficiency of 10.5 dB and 97%, respectively. Meanwhile, the antenna reconfigurability is realized by integrating RF MEMS switches on its right and left arm symmetrically. The presence of a T‐shaped Yagi‐Uda‐like parasitic further widened the beam steering angle to ±63° via mutual coupling. The obtained results demonstrate a good agreement between the simulation and measurement and have a huge potential for development of X‐band radar

A Wideband Reconfigurable Folded Planar Dipole Using MEMS And Hybrid Polymeric Substrates

A wideband reconfigurable folded planar dipole using hybrid polymeric substrates is proposed. Artificial Magnetic Conductor (AMC) is a periodic structure composed of rectangular patches integrated with Jerusalem Cross (JSC) slots and being located in between two substrates. The Perfect Magnetic Conductor (PMC)-like behaviour of the AMC structure enabled the printed folded dipole to be placed near to the proposed structure, resulting in a low-profile antenna with 5.11 dB gain operating at 9.41 GHz. The combined use of the polymeric substrate and the proposed AMC resulted in a 1 GHz of bandwidth. The proposed antenna is capable in beam steering on the xz-plane via the integration of radio frequency (RF) MEMS switches placed on the antenna feeding transmission line. Simulations and measurements show a satisfactory agreement, with a beam steering capability at least 30, bandwidth of 1 GHz and maximum gain of 5.11 dB

Multiband slot-loaded dipole antenna for WLAN and LTE-A applications

A multiband printed dipole antenna for wireless local area network (WLAN) and long-term evolution-advanced (LTEA) applications is investigated here. Its multiband characteristic is enabled by the Y-slot present in the upper arm of the dipole, while the antenna\u27s dimensions are 0.08λo × 0.384λo at the lowest operating frequency. It features bandwidth of 14.6% centred at 2.4 GHz, and ∼30.5% centred at 5.5 GHz for WLAN operation. An additional bandwidth of 6.9% centred at 3.5 GHz supporting LTE-A applications is also featured. Besides being compact, the proposed antenna radiates omnidirectionally with a gain of up to 4.09 dBi. Simulations and measurements are in good agreement