Addendum to "The Negative Capacitor, an Impedance Matching Element for Dielectric-Filled Transmission-Line" (Correspondence)

1968 ◽  
Vol 16 (6) ◽  
pp. 374-374
Author(s):  
A.J. Kelly
Keyword(s):  
Transmission Line ◽  
Impedance Matching ◽  
Matching Element ◽  
Line Correspondence

scholarly journals Bandwidth and gain enhancement of composite right left handed metamaterial transmission line planar antenna employing a non foster impedance matching circuit board

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Alibakhshikenari ◽  
Bal S. Virdee ◽  
Ayman A. Althuwayb ◽  
Leyre Azpilicueta ◽  
Naser Ojaroudi Parchin ◽  
...  
Keyword(s):  
Transmission Line ◽  
Impedance Matching ◽  
Circuit Board ◽  
Operating Frequency ◽  
Planar Antenna ◽  
Effective Technique ◽  
Input Capacitance ◽  
Gain Enhancement ◽  
Microstrip Patch ◽  
Left Handed

AbstractThe paper demonstrates an effective technique to significantly enhance the bandwidth and radiation gain of an otherwise narrowband composite right/left-handed transmission-line (CRLH-TL) antenna using a non-Foster impedance matching circuit (NF-IMC) without affecting the antenna’s stability. This is achieved by using the negative reactance of the NF-IMC to counteract the input capacitance of the antenna. Series capacitance of the CRLH-TL unit-cell is created by etching a dielectric spiral slot inside a rectangular microstrip patch that is grounded through a spiraled microstrip inductance. The overall size of the antenna, including the NF-IMC at its lowest operating frequency is 0.335λ0 × 0.137λ0 × 0.003λ0, where λ0 is the free-space wavelength at 1.4 GHz. The performance of the antenna was verified through actual measurements. The stable bandwidth of the antenna for |S11|≤ − 18 dB is greater than 1 GHz (1.4–2.45 GHz), which is significantly wider than the CRLH-TL antenna without the proposed impedance matching circuit. In addition, with the proposed technique the measured radiation gain and efficiency of the antenna are increased on average by 3.2 dBi and 31.5% over the operating frequency band.

Implementations of ACJ Technique in Different Four-Port Filter Networks

2021 ◽  
pp. 281-299
Author(s):  
Eugene A. Ogbodo
Keyword(s):  
Transmission Line ◽  
Impedance Matching ◽  
Main Challenge ◽  
The Common ◽  
Coupled Resonator

This chapter proposes the use of asynchronously coupled-resonator junctions (ACJ) in the design of a multi-input multi-output (MIMO) filtering network and a masthead combiner (MHC). By employing the resonator junctions, miniaturised circuits are achieved without using any transmission-line-based impedance matching circuits. The main challenge in the designs is the control and implementation of the external couplings at the common ports of this all-resonator-based MIMO filtering network and MHC. Both devices are four ports-based with the MIMO filtering network operating at 1.8, 2.1, and 2.6 GHz, while the MHC operates at the two channels of 1.8 and 2.1 GHz. The demonstrated designs achieved fractional bandwidths of 1.764 GHz to 1.836 GHz, 2.058 GHz to 2.142 GHz, and 2.548 GHz to 2.652 GHz, respectively. Good agreements have been achieved between the measurements of the prototype devices and the simulations.

scholarly journals A Wideband Antenna with Circular and Rectangular Shaped Slots for Mobile Phone Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Wei-Hua Zong ◽  
Xiao-Mei Yang ◽  
Xia Xiao ◽  
Shan-Dong Li ◽  
Xiang-Yang Wei ◽  
...  
Keyword(s):  
Transmission Line ◽  
Mobile Phone ◽  
Impedance Matching ◽  
Ground Plane ◽  
Slot Antenna ◽  
Microstrip Transmission Line ◽  
Rectangular Shape ◽  
Antenna Size ◽  
Wideband Antenna ◽  
Mobile Phone Applications

A wideband slot antenna for mobile phone applications is proposed. The antenna has two slots with open ends etched on the opposite edges of the ground plane. The main slot, of total length of 59 mm, is composed of a rectangle connected to a circle having radius of 5 mm. Another slot, having a rectangular shape with width of 2.8 mm and length of 26 mm, is employed to enhance the antenna bandwidth. The slots are fed by means of a rectangular monopole connected to a circular patch joined to a bent 50 Ω microstrip transmission line forming two right angles. To obtain a wideband impedance matching, the upper edge of the monopole and a part of the feeding line evolve along the top edge of the two slots. To reduce the antenna size, the upper part of the board above the slot (just 3 mm from the slot) is folded vertically to the ground plane. The measured bandwidth of the antenna is 0.698–1.10 GHz and 1.64–2.83 GHz covering LTE700/2300/2500, GSM850/900/1800/1900, and UMTS bands.

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