Efficient two-port antenna system for GSM=DCS=UMTS multimode mobile phones

The design of several two-port antenna systems for mobile phones is presented. All these structures are made up of two planar inverted-F antennas closely positioned on a small ground plane and radiating in the GSM900/DCS1800 and UMTS frequency bands. First, the antennas are simply associated at the top edge of the same printed circuit board. Thus, to improve their isolation and their total efficiency, a neutralisation effect is created by means of an optimised suspended line, which links the feeding strips of the radiators. The performance of these systems is measured and compared with theoretical results     

Small frequency agile antennas

Two small antennas loaded by varactor diodes and fed by a coplanar waveguide (CPW) and coaxial probe are presented. Varactor diodes made these antennas frequency agile. An important tuning frequency range of ~800 MHz was obtained and an application for different communication standards realised     

Design of an internal quad-band antenna for mobile phones

This letter presents the design of a compact Planar Inverted-F Antenna (PIFA) suitable for cellular telephone applications. The quarter-wavelength antenna combines the use of a slot, shorted parasitic patches and capacitive loads to achieve multiband operation. The commercial electromagnetic software IE3D is used to design and optimize the structure. The resulting antenna can operate from 880 to 960 MHz and 1710 to 2170 MHz covering GSM, DCS, PCS, and UMTS standards with a VSWR better than 2.5. Good agreement is found between simulated and measured results.     

Very compact double C-patch antenna

A miniaturised C-patch antenna excited by means of a coaxial probe is described. The antenna consists of two stacked C-shaped elements connected together with a vertical conducting plane. The antenna is designed on an air substrate and offers attractive dimensions, being five times lower than those of a conventional half wavelength microstrip patch antenna operating at the same frequency. A 10 dB bandwidth of 3% is obtained. The voltage standing wave ratio, radiation patterns, and electric surface current density are presented     

Antenne double C: un élément de tres petites dimensions

One can reduce dramatically the sizes of the planar antennas by introducing short-circuits in the structure of the antennas. In this paper, we present a miniaturized C-patch antenna excited by means of a coaxial probe. The antenna consists of two stacked C-shaped elements connected together with a vertical conducting plane. The antenna is designed on an air substrate and offers attractive dimensions, being five times lower than those of a conventional half wavelength microstrip patch antenna operating at the same frequency. Firstly, one presents the optimal geometry of the antenna and the results of the simulations which are compared with measurements in regard to the input impedance and radiation patterns. From this optimal configuration, a study parametric has been investigated for the all sizes of the antenna, in order to show the influence of each one on the resonance fre quency and the bandwidth. We will present also an application where this antenna is used in a proximity communication system between two computers.     

Logiciel de conception d’antennes à deux réflecteurs. application aux systèmes conformés elliptiques à alimentation décalée

To facilitate the design of dual reflector antennas, the interactive, graphic CA2R software package handles centrally or offset-fed structures with quadric or shaped reflectors. Surface shaping, based on geometrical optics, improves the antenna’s efficiency and the sidelobe level. Existing techniques are applied to an offset-fed antenna with an elliptical projected aperture. An original numerical method to minimize crosspolar components is also presented.     

Dual-frequency and broad-band antennas with stacked quarterwavelength elements

Original lightweight, low-cost, and compact air-filled planar antennas with short-circuited elements, fed by a coaxial probe, for dual-frequency (S-antenna) and wide-band applications (E-antenna) are investigated. The two-band frequency antenna is formed of two stacked quarter-wavelength elements, short-circuited along diametrically opposed planes. This structure offers two modes with different radiation characteristics. The ratio between the two frequencies can be closely controlled within a range varying from 1.3-2. A bandwidth of 30% for a VSWR <2 is demonstrated using two stacked quarter-wavelength elements short-circuited along the same plane. Numerical simulation results are compared with experiments and a very good agreement is observed. Radiation patterns and input impedance of both structures are measured and the effects of various physical parameters are presented     

Compact internal multiband antenna for mobile phone and WLAN standards

A novel internal planar inverted-F antenna (PIFA) suitable for handset terminals is presented. The structure combines shorted parasitic patches, capacitive loads and slots to achieve multiband operation. This compact antenna operates in the GSM, DCS, PCS, UMTS, HIPERLAN/2 and IEEE 802.11a bands within 2.5:1 voltage standing wave ratio (VSWR) and with good efficiency.     

Conception d’une antenne bibande à large bande pour la téléphonie mobile

The next mobile communication generation needs to be multi-band but also require a large bandwidth behaviour for each band, all this associated with dimensions as small as possible. The paper presents a radiating structure having these different properties. The realisation of this antenna is obtained using a folded planar metallic elements, ground wires and open quarter-wave slots. The influence of each technique and parameter is studied, analysed and optimised to obtain a single radiating dual-band / large bandwidth element, operating in GSM900, umts and also ism 2.4 communication standards. The radiation pattern of this antenna is suitable for mobile handset applications.     

The C-patch: a small microstrip element

Presents a radiating element operating in the UHF and L-bands; its dimensions are smaller than those of conventional square or circular elements. For this type of antenna, good matching is obtained with a coaxial feed, and the omnidirectional radiation pattern is achieved using linear polarisation. The bandwidth, however, remains somewhat narrow.<>