On the Design of a New 4x4 Coupler for C Band based on a 180° Coupler at Microstrip Technology

Abstract. Radar systems for contactless vital sign monitoring are well known and an actual object of research. These radar-based sensors could be used for monitoring of elderly people in their homes but also for detecting the activity of prisoners and to control electrical devices (light, audio, etc.) in smart living environments. Mostly these sensors are foreseen to be mounted on the ceiling in the middle of a room. In retirement homes the rooms are mostly rectangular and of standardized size. Furniture like beds and seating are found at the borders or the corners of the room. As the propagation path from the center of the room ceiling to the borders and corners of a room is 1.4 and 1.7 time longer the power reflected by people located there is 6 or even 10 dB lower than if located in the center of the room. Furthermore classical antennas in microstrip technology are strengthening radiation in broadside direction. Radar systems with only one single planar antenna must be mounted horizontally aligned when measuring in all directions. Thus an antenna pattern which is increasing radiation in the room corners and borders for compensation of free space loss is needed. In this contribution a specification of classical room sizes in retirement homes are given. A method for shaping the antenna gain in the E-plane by an one-dimensional series-fed traveling wave patch array and in the H-plane by an antenna feeding network for improvement of people detection in the room borders and corners is presented for a 24 GHz digital beamforming (DBF) radar system. The feeding network is a parallel-fed power divider for microstrip patch antennas at 24 GHz. Both approaches are explained in theory. The design parameters and the layout of the antennas are given. The simulation of the antenna arrays are executed with CST MWS. Simulations and measurements of the proposed antennas are compared to each other. Both antennas are used for the transmit and the receive channel either. The sensor topology of the radar system is explained. Furthermore the measurement results of the protoype are presented and discussed.

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A study of the ground plane effect in passband filters using OSRR cells

DYNA ◽

10.15446/dyna.v82n193.42550 ◽

2015 ◽

Vol 82 (193) ◽

pp. 9-15

Author(s):

Iván Eduardo Díaz Pardo ◽

Carlos Arturo Suárez Fajardo ◽

Gustavo Adolfo Puerto Leguizamón

Keyword(s):

Ground Plane ◽

The Other ◽

Ring Resonators ◽

Considerable Reduction ◽

Split Ring ◽

Microstrip Technology ◽

Split Ring Resonators ◽

Other Hand

This paper presents the study of the ground plane effect in passband filters using metamaterial cells in Open Split Ring Resonators (OSRR) structures on microstrip substrates. Three different configurations have been proposed, namely: by removing partially the ground plane of the OSRR cell back end, by windows design over the ground plane at the back end of each cell and by placing a full ground plane. The conducted analysis shows that the filter transmission response featuring a ground plane including windows proved to be the most flattened with the middle bandwidth of the three configurations. On the other hand, the performance of these filters is similar to a conventional filter based on three-pole microstrip technology but with a considerable reduction in size of about 60%.

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A Microstrip Low-Pass Filter Design Using a Modified Radial Resonator in the Application of Aircraft Distance Measurement Equipment

ECTI Transactions on Electrical Engineering, Electronics, and Communications ◽

10.37936/ecti-eec.2021193.241039 ◽

2021 ◽

Vol 19 (3) ◽

pp. 260-267

Author(s):

Hamid Radmanesh

Keyword(s):

Communication Systems ◽

Filter Design ◽

Model Performance ◽

Distance Measurement ◽

Measurement Equipment ◽

Microstrip Technology ◽

Pass Filter ◽

Low Pass Filter ◽

Low Pass ◽

Radial Resonator

In this paper, the application of microstrip technology is investigated in low-pass filters. A cascade microstrip low-pass filter with a sharp frequency response and a good cut-off bandwidth is presented using a modified radial resonator. The advantages of this proposed filter include minor losses in the transit band as well as the desired return. This filter design shows consistency when compared with the results of simulation and model performance. A comparison between the parameter values of this filter and previous structures indicates that it is desirable. The proposed filter can be used in modern communication systems such as aircraft distance measurement equipment (DME) antenna.

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CNT-Based Inkjet-Printed RF Gas Sensor: Modification of Substrate Properties during the Fabrication Process

Sensors ◽

10.3390/s19081768 ◽

2019 ◽

Vol 19 (8) ◽

pp. 1768 ◽

Cited By ~ 7

Author(s):

Julien George ◽

Aymen Abdelghani ◽

Prince Bahoumina ◽

Olivier Tantot ◽

Dominique Baillargeat ◽

...

Keyword(s):

Gas Sensor ◽

Electrical Characterization ◽

Sensitive Material ◽

Paper Substrate ◽

Microstrip Technology ◽

Multi Wall Carbon Nanotubes ◽

Silver Ink ◽

Substrate Properties ◽

Printed Materials ◽

The Impact

This paper presents the feasibility of a fully inkjet-printed, microwave flexible gas sensor based on a resonant electromagnetic transducer in microstrip technology and the impact of the printing process that affects the characteristics of the gas sensor. The sensor is fabricated using silver ink and multi-wall carbon nanotubes (MWCNTs) embedded in poly (3,4-ethylenedioxythiophene) polystyrene (PEDOT: PSS-MWCNTs) as sensitive material for Volatile Organic Compounds (VOCs) detection. Particular attention is paid to the characterization of the printed materials and the paper substrate. The manufacturing process results in a change in relative permittivity of the paper substrate by nearly 20%. Electrical characterization, made in the presence of gas, validates our theoretical approach and the radiofrequency (RF) gas sensor proof of concept.

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