A Polyimide-Based Flexible Monopole Antenna Fed by a Coplanar Waveguide

Abstract

A 2.4 GHz flexible monopole antenna fed by a coplanar waveguide (CPW) was presented on polyimide (PI) as the dielectric substrate, which was fabricated by in situ self-metallization. The technology does not depend on expensive equipment or complex experimental environments, including hydrolysis, ion exchange, and reduction reaction. The measurement results show that the resonance frequency of the proposed antenna is 2.28 GHz, the bandwidth is 2.06–2.74 GHz, and the relative bandwidth is 28.33% under the flat state. The bending and folding test was also carried out. Whether it was flat, bent, or folded, the measured results met the requirements of the antenna. A fatigue test was carried out to illustrate that the prepared film has high mechanical flexibility, which expands the application field of antenna.

In Situ Growth of Silver Film on Polyimide with Tuned Morphologies for Flexible Electronics

“…On the other hand, the ion-exchange technique coupled with the printed-mask method has been successfully applied to the fabrication of high-quality flexible antennas in our previous work . Patterned functional devices and circuits can be fabricated by this technique, such as flexible humidity sensor with an interdigital electrode, strain sensor, serpentine-shaped temperature sensor, and different antennas, ,, proving promising application in flexible electronics.…”

“…Preparation of conductive films or patterns on polymer film has attracted a lot of interest because of their extensive applications in flexible electronics, such as wearable devices, flexible antenna, integrated circuits, etc. − Silver (Ag) has long been the good choice as the conductive metal due to its excellent conductive property and good mechanical compliance with polyimide (PI) substrate. , Consequently, plenty of approaches to fabricate Ag--PI composite have been reported, which mainly include metal coating and direct metallization of PI. The first one to fabricate Ag coatings contains electrochemical coating, chemical/physical vapor deposition, sputtering, and printing techniques. − However, poor adhesion between Ag coatings and PI substrate hinders their practical application.…”

A Review on Flexible Printed Antennas for Futuristic Applications

“… Textile industry -Embedding flexible antennas into clothing makes the attire transform into smart interface for the communication between the user and the network. The antennas should be lightweight, resistant to washing and of low cost for manufacturing and advertising [11]. Conductive textile materials are needed for the conductive layer (ground plane) and nonconductive textile materials are required for the dielectric layer [67].…”

“…They have now become the assemblage of numerous devices which are composed of organic substances as a substrate [8]. Flexible electronics (flex circuits) is a technology for assembling electronic circuits by electronic devices on flexible substrates, such as, conductive polymer [9], conductive textile [10], polyimide [11], Teflon [12], liquid crystal polymers (LCPs) [13], etc. FES technology is used for developing passive as well as active electronic devices.…”

Preparation and Characterization of Transparent Polyimide Nanocomposite Films with Potential Applications as Spacecraft Antenna Substrates with Low Dielectric Features and Good Sustainability in Atomic-Oxygen Environments

“…In addition, the low dielectric properties could also provide the antenna with better impedance matching and higher gain compared to conventional high-dielectric-constant substrates [ 15 ]. The common PI antenna substrates PI PMDA-ODA exhibited a D k and D f value of 3.2 and 0.02 at 1 MHz frequency, respectively [ 16 , 17 , 18 ]. Thus, either the poor AO resistance or the high dielectric properties of the current PI PMDA-ODA substrates could not meet the property requirements of advanced antennas for LEO spacecraft.…”