Electrically tunable rectangular microstrip antenna

Abstract

The tunable microstrip patch antenna using electrostatic force is presented. The antenna was patterned on the top side of a (poly-ethylene terephthalte) film. When a DC bias voltage is applied between the flexible patch and the fixed ground plane, the flexible patch bends downwards towards the fixed ground plane owing to the electrostatic force of attraction. The bending of the flexible patch decreases the air-gap, and consequently the effective permittivity of the antenna is increased. By increasing effective permittivity, the resonant frequency is shifted downwards. For the tunable microstrip patch antennas of 6, 8 and 10 GHz at DC bias 150 V, the measured tuning ranges were 217.04, 242.58 and 365.63 MHz, respectively.Introduction: In recent years there has been considerable interest in the development of tunable antennas because of the increasing number of global wireless standards [1][2][3]. Multiband antennas are needed in order to achieve miniaturisation in mobile and wireless data communication systems such as PCS, Bluetooth, and wireless local-area network (LAN) applications. In [4], the resonant frequency of the microstrip patch antenna was tuned using a varactor diode at both radiating edges. In [5], tunable microstrip antennas using piezoelectric substrate such as a PZT, LiNbO 3 and quartz were proposed. However, the frequency shifts in these papers are not enough for wireless LAN.In this Letter, we propose a new type of tunable microstrip patch antenna using electrostatic force. The antenna with the air-gap structure was fabricated with a flexible substrate. When the air-gap thickness deforms by applying a DC bias voltage between the patch and the ground plane, the resonant frequency is shifted as well. Measurement and simulation of the frequency shifts were carried out and good agreement has been obtained.

A study on frequency tuning and miniaturization of a ground slotted rectangular microstrip patch antenna built with different dielectric substrates

“…For the past years, dual-polarized technology has been extensively utilized to increase communication capability and reduce the effects of multipath fading. Many broadband dual-polarized antennas have been presented for base station applications [1][2][3][4][5][6][7][8][9][10][11]. By using the aperture-coupled [1] and L-probe feeding technology [2], antennas [1,2] realized the impedance bandwidth of 17% (SWR < 2) and 19.8% (SWR < 1.5).…”

“…Sever broadband dualpolarized antennas have been researched in Refs, [3][4][5], but their impedance bandwidth still couldn't cover 2G/3G/LTE bands. By adding parasitic elements [6][7][8][9], a improved broadband impedance bandwidth can be obtained. A new type of magnetoelectric dipole antenna for base stations was presented [10], which achieved wide impedance bandwidth, stable radiation pattern, stable gain and low cross polarization.…”

A Millimeter-Wave Inflatable Frequency-Agile Elastomeric Antenna

“…3(b). The designed structure and actuation scheme enable to overcome limitations for similar designs due to electrostatic actuation that has a limited displacement and less deformable materials that require larger actuation forces [8]- [10].…”

“…Reconfigurable antennas using plastic deformation magnetic actuation [6] and tunable microelectromechanical system (MEMS) capacitors [7] were also reported. In [8], an electrostatically actuated micromachined copper ground plane was used to tune a microstrip antenna from 16 [10] with a tunability of 3.6% at 10 GHz. One of the key issues for elaborating mechanically reconfigurable antennas at millimeter waves consists in finding materials with suitable electromagnetic and mechanical properties.…”

Effect of rectangular ground slot in a microstrip line fed monopole UWB antenna for multiband applications

“…Resonance frequency tuning is obtained by loading the antenna with a coplanar waveguide (CPW) stub on which periodic structure of variable MEMS capacitors are placed. An electrically tunable rectangular microstrip antenna is presented in . The resonance frequency of the antenna is tuned by controlling the thickness of the air gap between the patch and the ground plane.…”