Cable Effects on Measuring Small Planar UWB Monopole Antennas

IEEE Trans. Antennas Propagat.

2015

The design of a simple planar polarization reconfigurable monopole antenna for the Global Navigation Satellite System (GNSS) and Personal Communications System (PCS) is presented. The antenna consists of two meandered monopoles, a feeding network using the Wilkinson power divider, two switchable 90 -phase shifters implemented using -microstrip lines and a defected ground structure (DGS). The meandered monopoles resonating at about 1.55 GHz are placed perpendicular to each other. The input signal is divided into two signals with equal amplitude and phase by the power divider and fed to the meandered monopoles via the phase shifters. The two signals arriving at the two monopoles have a phase difference of 90 , or 0 , depending on the phase shifters controlled using six PIN-diode switches, hence generating a right/left-handed circularly polarized (CP) or linearly polarized (LP) signal. We propose a novel biasing technique to control the six PIN diodes using five voltages. Measurement results show that the antenna in CP has an impedance bandwidth of 1.06-1.64 GHz and an axial-ratio bandwidth of 1.43-1.84 GHz, and in LP has an impedance bandwidth of 1.63-1.88 GHz. Simulated and measured results on S11, AR, radiation pattern, and gains show good agreements.

Section: Simulation and Measurement Resultsmentioning

confidence: 93%

A Simple Planar Polarization Reconfigurable Monopole Antenna for GNSS/PCS

Cao

IEEE Trans. Antennas Propagat.

2015

“…This eliminates the insertion losses caused by the cables and the bias T, and so on in the measured results. Figure shows large discrepancies between the simulated and measured results, which are mainly due to the cable effects explained as follows . When measuring monopole antennas with finite grounds, some currents will flow back to the outer surface of the feeding cable.…”

Section: Simulation and Measurement Resultsmentioning

confidence: 96%

Frequency‐Tunable Monopole Antenna for Wimax Applications

Sun

Micro & Optical Tech Letters

2013

This article presents a planar dual‐band monopole antenna with a frequency‐tunable band for use in wireless devices of the 2.4 and 3.4 GHz worldwide interoperability for microwave access (WiMAX) system. The antenna has two radiating branches acting as monopoles and resonating at around 2.4 GHz (lower band) and 3.4 GHz (higher band). A varactor is placed on the radiating branch responsible for the lower band. A very simple DC biasing circuit is designed for reverse‐biasing the varactor. By varying the DC‐bias voltages from 0 to 12 V for the varactor, the lower band of the antenna can be continuously tuned from 2.3 to 2.83 GHz, covering the frequency bands from 2.3 to 2.4 GHz and 2.5 to 2.7 GHz for the WiMAX system. The antenna has a small overall size of 40 × 35 × 0.8 mm3 with a compact radiator of only 14.5 × 8.2 mm2. The antenna performance in terms of reflection coefficient, radiation pattern, peak gain, and efficiency is studied using computer simulation. For verification of simulation results, the antenna is fabricated and measured. The feeding cable used in measurement causes substantial discrepancies between the simulated and measured simulation results. To study the cable effects, a computer simulation model is included for studies. With the cable model, the simulated and measured results agree very well. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1902–1907, 2013

“…In computer simulation, no feeding cable is used. When measuring small monopoles at low frequencies where the finite grounds become electrically small, some currents will flow back to the outer surface of the feeding cable, causing secondary radiation from the cable [11,12] and inaccuracies to the measured radiation patterns. Figure 5 shows the prototyped antenna connected with the short feeding cable.…”

Section: Simulation and Measurement Resultsmentioning

confidence: 99%

A compact monopole antenna for WLAN applications

Sun

Micro & Optical Tech Letters

2013

The design of a compact antenna for use in wireless devices of the 2.4/5.2/5.8‐GHz wireless‐local‐area network (WLAN) is presented. The antenna consists of an L‐shaped monopole radiator (L‐element) with microstrip‐fed on one side of the substrate and a protruding meander‐microstrip ground stub (M‐stub) on the other side. The L‐element and the M‐stub generate a high‐frequency band at around 5.4 GHz for the high WLAN bands and a low‐frequency band at around 2.44 GHz for the low WLAN band, respectively. The antenna has a very compact size of only 25 × 25mm2, including the ground plane. Computer simulation is used to study, design, and optimize the antenna. For verification of the simulated performance, the antenna is fabricated and measured using the antenna measurement system, Satimo Stargate. The effects of the feeding cable used in measurement cause discrepancies between the simulated and measured performances. To verify the cable effects, the feeding cable is modeled in simulation. With the use of the cable model, the simulated and measured performances show very good agreements. A practical application of the proposed antenna is also studied by installing it on a printed‐circuit board having the similar size of a smartphone. The impedance bandwidth, radiation pattern, peak gain, and efficiency of the antenna are studied and presented. Results show that the antenna is a potential candidate for small WLAN wireless devices. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:469–475, 2014