Tuning techniques for planar inverted-F antenna

User terminals of modern mobile communication systems require efficient, low profile antennas, capable of broadband and multi-band operation. In that respect, planar inverted-F antenna (PIFA) designs have emerged that explore the trade-off between the height above the ground-plane and the achievable effective bandwidth. Further possible bandwidth enhancements are studied, as is multi-band operation by switching and tuning the resonant frequency of the PIFA, while maintaining a low height above the ground plane     

Dual-frequency planar antenna for handsets

Cellular telephone handsets are now being designed to have dual-mode capabilities. In particular, GSM and DCS1800 modes are used in Europe. And PCS and AMPS modes are used in the USA. A novel planar dualband internal antenna for handsets which operates in the ~0.9 and 1.8 GHz bands is proposed. The dualband antenna has almost the same size as a conventional internal antenna operating in the 0.9 GHz band. Good dual-band operation was obtained for frequency ratios in the range 1.3-2.7     

FDTD方法分析新型双频平面倒F手机天线

设计了一种新型单馈点双频平面倒F手机天线(PIFA),用时域有限差分方法(FDTD)计算了该天线的电流分布和辐射方向图,以验证设计原理。该天线可用于GSM和DCS1800两个系统,中心工作频率分别为0.94GHz和1.8GHz,反射损失小于-10dB的阻抗带宽可达到10％以上。通过简单调节天线的两个参数,天线两个频段的中心工作频率独立可调,来消除手机设计制造误差对天线工作频率的影响。     

Single-feed dual-band planar inverted-F antenna with U-shaped slot

The development of small integrated antennas plays a significant role in the progress of rapidly expanding wireless communication applications. This paper describes a novel dual-band planar inverted-F antenna (PIFA) for wireless local area network applications. The proposed PIFA uses single feed only. A novel top-plate geometry, a U-shaped slot, is discussed. An example is given for this novel slot shape for frequency bands of 2.4 and 5.2 GHz. Simulation based upon the method of moments (MoM) is used to model the performance of the antenna. Comparisons with results measured on fabricated antenna structures are provided for simulations validation.     

Diversity metal-plate planar inverted-F antenna for WLAN operation

A diversity metal-plate planar inverted-F antenna (PIFA) mounted on a PCMCIA network card for WLAN operation in the 2.4 GHz band is presented. The diversity antenna comprises two back-to-back PIFAs, with their shorting plates facing each other, and has a small protruded length of 6 mm only, when the PCMCIA network card is inserted into the interface slot of a laptop. The antenna shows good antenna gain, and can provide spatial diversity to combat the multipath interference problem.     

Wideband planar inverted-F antenna with meandering shorting strip

A new wideband planar inverted-F antenna (PIFA) is introduced. The proposed antenna is based on a simple PIFA, where the shorting strip is modified into a meandering shape such that the antenna can have wideband characteristics. The antenna finds an impedance bandwidth of 45.2% for S11 < -10 dB from 1.565 to 2.48 GHz which can cover the GPS, DCS, IMT-2000, 2.4 GHz WLAN applications. The maximum antenna gains are 1.68, 1.83, 1.90 and 1.78 dBi correspondingly.     

Miniaturized active stepped impedance planar inverted-F antenna using common ground

This paper presents a compact active integrated antenna (AIA) comprising of class-A power amplifier (PA) and stepped impedance planar inverted-F antenna (PIFA). In the proposed design, a common ground is used for both PA and PIFA, resulting a compact antenna of size 0.14λ₀ × 0.11λ₀ × 0.01λ₀ (λ₀ is free space wavelength at 0.85 GHz). Moreover, it is demonstrated that by using the stepped impedance radiator the operating frequency of the active PIFA is shifted down from its natural resonant frequency of 1.36 GHz to 0.85 GHz, offering an extensive size reduction of 80%. This active integration increases the passive antenna gain through the effective loading of the antenna to the power amplifier. The measured result indicates that the active and passive antennas achieved the gain of 15.7 dB and 3.81 dBi, respectively after the integration. In addition, the maximum SAR value of antenna is found to be 0.64 W/kg.     

一种宽带小型化的三频PIFA天线

综合多种技术,提出了一种宽频带小型化的三频PIFA天线。基于缝隙加载技术,在辐射贴片上开双L形槽以形成多个电流路径,从而产生多个谐振频率;引入折叠的辐射片结构以缩小天线的轮廓;通过较宽的馈电带片激励来展开天线各个频段的带宽。天线的仿真与测试结果吻合较好,证实了该新型天线具有较宽的工作频带和良好的辐射特性,能较好地满足GSM/DCS/ISM三个频段的要求,还覆盖了S-DMB频段,具有一定的实用价值。     

Integrating microgenetic algorithms with TLM method for dual-band planar inverted-F antenna design

The efficient coupling between microgenetic algorithms (/spl mu/GA) and the transmission line matrix method (TLM) to design two planar inverted-F antennas (PIFAs) for dual-band DCS/WLAN and GSM/UMTS standards, respectively, is presented. Measurement results of the /spl mu/GA/TLM optimised designs show good agreement with numerical simulation for a GSM/UMTS antenna.     

Design and analysis of an R-shaped dual-band planar inverted-F antenna for vehicular applications

A dual-band R-shaped planar inverted-F antenna is proposed for vehicular application. Utilization of this unique geometry dual-frequency operation is achieved with a single feed. The proposed antenna operates in the 225- and 450-MHz bands. Input impedance and return loss data as function of various antenna parameters are presented, which show that parameters can be adjusted in order to obtain optimum tuning. Radiation pattern data for the antenna mounted on the roof of two types of vehicles are given. The pattern in the low-frequency band is essentially omnidirectional while that in the high-frequency band is directional and normal to the antenna surface. With proper scaling, this antenna may be suitable for dual-band GSM 900/1800-MHz phone applications.     

A compact planar inverted-F antenna with a PBG-type ground plane for mobile communications

The ground plane affects the characteristics of a planar inverted-F antenna (PIFA) significantly. Using the idea of the high-impedance surface to construct the ground plane, a new type of compact PIFA with a photonic bandgap type (PBG-type) ground plane is proposed. Both the traditional PIFA and the proposed antenna are analyzed using the finite-difference time-domain (FDTD) method in detail. It is found that the two antennas have similar directivity pattern characteristics, but the size of the latter can be reduced obviously. The results also show that the bandwidth of a traditional PIFA is not greatly affected by the thickness of the metallic ground plane and that the shapes of the directivity patterns are not greatly affected by the ground plane under the small size condition. The operating-frequency band of the proposed antenna can be adjusted by changing the dielectric substrate thickness of the ground plane. They are suitable for mobile communication applications.     

Finite-difference time-domain analysis of a stacked dual-frequencymicrostrip planar inverted-F antenna for mobile telephone handsets

We describe a stacked, dual-frequency microstrip planar inverted-F antenna (DF-PIFA) for mobile telephone handsets that can concurrently work in two frequency-bands, viz., those associated with the GSM and DCS 1800 systems operating at 0.9 GHz and 1.8 GHz, respectively. The proposed microstrip DF-PIFA is fed by a coaxial line, as opposed to two separated feed lines used in the conventional design. The design is carried out in a systematic manner and involves two steps. We begin with an initial configuration of the PIFA that is based on a standard design for a microstrip patch antenna fed by a coaxial line and is derived from an empirical approximation in conjunction with a transmission line model. Next, we employ a computer-aided design (CAD) tool, based on the nonuniform finite-difference time-domain (NU-FDTD) Maxwell solver, to optimize the performance characteristics of the DF-PIFA, including the return loss, the matching of the input impedance, and the far-field radiation patterns     

Planar inverted-F antenna for radio frequency identification

A small and low-cost antenna solution for radio frequency identification (RFID) tags is presented. The impedance of the antenna is designed to match directly to the impedance of the RFID microchip. Also, the impedance of the antenna is immune to the platform. Thus, the antenna is applicable in many different environments. The design and measurement results are reported and discussed.     

Planar inverted-F antenna with rectangular cap shape

The novel geometry of the planar inverted-F antenna (PIFA), similar to the metal case (or cap) of a commercial RF module, is presented for Zigbee application at 2.4 GHz band. This design has been examined by simulations. The fabricated prototype has compact dimensions of 18times18times2 mm with rectangular cap shape. Test results show good broad-side radiation patterns and impedance bandwidth of 87 MHz covering the Zigbee frequency band. By using the proposed PIFA, a compact RF module integrated with antenna can be realised     

Mutual coupling between identical planar inverted-F antennas

Mutual coupling between two identical planar inverted-F antennas (PIFA) located on an infinite ground plane is studied numerically. Several arrangements of side-by-side, collinear, parallel-in-echelon, and orthogonal PIFA antennas with element spacing varying from $0.06\lambda$ to $1.20\lambda$ are investigated at the design frequency of 1.9 GHz, and in the $-6\mathrm{dB}$ bandwidth between 1.8 and 2.0 GHz. It is found that choosing configurations that maximizes the separation between the open-end of the PIFAs reduces the mutual coupling.     

Dual-frequency stacked annular-ring microstrip antenna

Experimental results of a dual-frequency microstrip antenna consisting of two stacked annular rings of outer radii 5 cm and inner radii 2.5 cm are presented. Fabricated on a Duroid substrate with relative permittivity 2.32 and thickness 0.159 cm, the separations of the two resonant frequencies range from 6.30-9.36 percent for the first three modes. The frequency separations can be altered by means of an adjustable air gap between the lower ring and the upper substrate.     

Dual-frequency stacked shorted patch antenna

A small dual-frequency printed antenna based on a stacked shorted patch configuration with a common feed is presented. The antenna allows for relatively independent control of the two resonant frequencies. The new concept is demonstrated and the measured performance of the radiator is given.     

Dual-frequency slotted rectangular microstrip antenna

By embedding a pair of properly-bent narrow slots close to the non-radiating edges of a rectangular microstrip patch, a novel dual-frequency operation of microstrip antennas using a single probe feed is proposed and experimentally studied. The two operating frequencies have parallel polarisation planes and similar broadside radiation patterns, and the frequency ratio of the two frequencies is controlled by the bent angle of the embedded slots. Details of the obtained dual-frequency performance are presented and discussed     

Compact internal inverted-F antenna for USB dongle applications

A multiband inverted-F antenna that operates over WiBro, WLAN, WiMax and S-DMB frequency bands is proposed. The antenna consists of an inverted-F element and four stubs. The measured return loss of the designed antenna over the frequency band of interest is better than 10 dB. Good return loss and radiation pattern characteristics have been obtained in the desired frequency band.