Internal PIFA for 2.4/5 GHz WLAN applications

An internal planar inverted-F antenna (PIFA) for 2.4 GHz Bluetooth and 5 GHz WLAN applications is presented. The proposed antenna has an impedance bandwidth of 110 MHz in Bluetooth band and 900 MHz near 5 GHz in WLAN band within 2:1 VSWR, and an approximately omnidirectional radiation pattern can be obtained. These features are suitable for 2.4/5 GHz WLAN applications     

Miniature PIFA without empty space for 2.4 GHz ISM band applications

A novel miniature planar inverted-F antenna (PIFA) design without empty space is presented for 2.4 GHz ISM band applications. The antenna fabricated on an FR4 substrate has an overall size of only 10 (L) x 3 (W) x 3.5 (H) mm³ to be embedded inside the portable devices. By properly adding a shorting pin and etching a bent slot, the operating frequency of the antenna can be lowered more flexibly. Moreover, owing to no additional empty space, the circuit routing on the PCB is permitted underneath and around the antenna. The impedance bandwidth of the antenna is about 160 MHz from 2.39 to 2.55 GHz. Good omnidirectional radiation pattern with appreciable gain across the band can be obtained so that the proposed antenna is suitable for Bluetooth and WLAN applications.     

Compact wideband antenna for 2.4 GHz WLAN applications

A novel compact wideband antenna for wireless local area network (WLAN) applications in the 2.4 GHz band is presented. The proposed low profile antenna of dimensions 15/spl times/14.5/spl times/1.6 mm offers 18.6% bandwidth and an average gain of /spl sim/5 dBi. The antenna can be excited directly using a 50 /spl Omega/ coaxial probe.     

Printed compact dual band antenna for 2.4 and 5 GHz ISM band applications

A printed compact dipole antenna for dual ISM band (2.44 and 5 GHz) is presented. The proposed antenna fed by using a 50 /spl Omega/ coaxial line occupies a volume of 15/spl times/40/spl times/1 mm/sup 3/ (FR-4, permittivity 4.6). The impedance bandwidth for 10 dB return loss is about 400 MHz (from 2170 to 2570 MHz) at 2.4 GHz band and over 2300 MHz (from 4690 to beyond 7000 MHz) at 5 GHz band. The measured radiation gains range from 1.20 to 1.41 dBi at 2.4 GHz band and from 2.25 to 3.44 dBi at 5 GHz band, respectively.     

Compact planar multiband antenna for GPS, DCS, 2.4/5.8 GHz WLAN applications

A compact single-feed multiband planar antenna configuration suitable for GPS, DCS, 2.4/5.8 GHz WLAN applications is presented. The antenna has dimensions 38/spl times/3/spl times/1.6 mm and offers good radiation and reflection characteristics in the above frequency bands. The antenna has a simple geometry and can be easily fed using a 50 /spl Omega/ coaxial probe.     

一种2.4GHz小型化微带天线

设计了一种新型小型宽频带微带天线。通过在贴片和地板上”开槽”形成特殊形状的方法,达到小型化和宽频带的目的。仿真结果表明,在中心频率2．4GHz时,相对带宽为15％,与原始的理论值相比较,小型化后的天线尺寸缩小了33％。     

Sheetlike Waveguide for 2.4 GHz and 5 GHz Bands

We present a useful design for a free access mat which supports two frequency bands of 2.4 GHz and 5 GHz. The free access mat is a sheet‐shaped waveguide which consists of a tightly coupled double‐layered microstrip resonator array. It provides easy access for devices in short‐range wireless communications. Interference is a common problem with conventional applications which use free space transmission. Our proposed wireless access system uses a subsidiary waveguide, the free access mat. Wireless devices are proximately coupled to the free access mat through which the coupled electromagnetic (EM) wave transmits. The arrival domain of the EM wave of an application is therefore limited to an area close to the free access mat. Wireless devices can be coupled to the free access mat at an arbitrary position without contact. We previously presented a free access mat for a single frequency band. This paper presents a free access mat for the two frequency bands of 2.4 GHz and 5 GHz. The free access mat uses a ring patch resonator array which is easily excited by typical antennas and is resistant to interference. These characteristics are demonstrated by numerical simulation and confirmed by experiment.     

Surface-mount dual-loop antenna for 2.4/5 GHz WLAN operation

A surface-mount dual-loop antenna suitable for dual-frequency WLAN operation is presented. For achieving dual-frequency operation with a compact size, the antenna comprises two loop strips of different sizes printed on a flexible printed circuit board, which is then bent and attached onto a foam base of compact size. The antenna shows an attractive feature of high antenna gain, about 4 and 5 dBi for frequencies across the 2.4 and 5 GHz WLAN bands, respectively.     

Dual-band bidirectional high gain antenna for WLAN 2.4/5.8 GHz applications

Adual-band bidirectional high gain dipole array antenna forWLAN(2.4/ 5.8 GHz) applications is proposed and analysed. The array antenna is composed of four elements. Each element is a double-sided printed dipole which is fed with a balanced twin transmission line. Measured results agree very well with simulation results. According to the measured results, the bandwidth with a VSWR less than two is about 400 and 1100 MHz in the two bands, respectively. Good shaped patterns are also achieved. The measured gains for the 2.4 and 5.8 GHz bands are between 4.8?6 and 6?8.8 dBi, respectively.     

Modified inverted-L monopole antenna for 2.4/5 GHz dual-band operations

A novel compact modified inverted-L monopole antenna for dual-band operation is proposed. The proposed antenna is designed to operate in 2.4 GHz (2400-2484 MHz) and 5 GHz (5150-5825 MHz) bands for WLAN applications in IEEE 802.11a/b and HIPERLAN/2 systems. The method to realise the desired dual-band operation is by introducing a meandered wire and a conducting triangular section to a conventional inverted-L monopole, which results in a small antenna size of 7/spl times/18 mm/sup 2/. Good impedance bandwidth performance is also observed.     

Compact dualband rectangular microstrip patch antenna for 2.4/5.12-GHz wireless applications

A dual-band antenna is proposed for WLAN and WiMAX frequency bands. Two resonance frequencies are found to be 2.45 and 5.125 GHz and ?10 dB bandwidth of lower and upper resonance frequencies are 4.13 and 8.82 % respectively. It is observed that frequency ratio is more sensitive with the dimensions of L-shaped slot. The frequency ratio of the antenna for a given dimension of L-slot is found to be 2.092 and gain of the antenna is 3.9 dBi for lower resonance whereas 6 dBi at upper resonance. The theoretical results are compared with the reported experimental result as well as simulated results obtained from IE3D simulation software which are in close agreement.     

A Miniature Dielectric Loaded Monopole Antenna for 2.4/5 GHz WLAN Applications

A miniature dielectric loaded monopole antenna fed by coplanar waveguide (CPW) is proposed for WLAN applications in the 2.4/5-GHz bands. The dielectric material is a cylindrical block of ceramic with a 22 permittivity. The back side of the ceramic material with a simplified open-end tuning stub is also proposed. The prototype has been designed and fabricated and found to have bandwidths of 8% and 35.3% at the resonant frequencies of 2.48 and 5.60GHz, respectively, and the radiation patterns measured at resonance frequencies are very close to omnidirectional in the H-plane. The characteristics of the proposed antenna has been investigated using simulation software HFSS and experimental results. The measured and simulated results show excellent agreement     

8mW 17/24 GHz dual-band CMOS low-noise amplifier for ISM-band application

As wireless applications expand, requirements for a radio that can support multi-bands and multi-standards are continuously increasing. In a single-chip radio, a low noise amplifier (LNA) plays an important role in the noise performance or sensitivity of the total receiver chain. Although up to now a number of broadband and dualband LNAs have been reported with good performance in CMOS technology, most previous work has focused on a low frequency range, below 10 GHz. In general a dual-band LNA can be achieved by combining two LNAs in parallel for each narrow band [1]. However, this approach demands twice the power dissipation, a large chip area and therefore a significant increase in cost. Recently the low power and compact-sized dual-band LNA using a switching inductor, capacitor and concurrent method also has been reported [2?4]. In this Letter a low power concurrent dual-band LNA is proposed which is suitable for 17.1?17.3 GHz and 24?24.25 GHz industrial, scientific and medical (ISM) band application.     

CPW-fed circular slot antenna with slit back-patch for 2.4/5 GHz dual-band operation

A circular slot antenna fed by a coplanar waveguide (CPW) is proposed for dual-band operations. Dual frequency bands that cover the 2.4 GHz (2400-2484 MHz) and 5 GHz (5150-5825 MHz) bands were obtained by embedding a pair of slits in the circular back-patch that is printed on the backside of the substrate and concentric with the circular slot. This design resulted in broadside far-field patterns with low cross-polarisation levels in both frequency bands and a small antenna size of 40/spl times/40 mm with the ground plane regarded as part of the antenna structure.     

Printed antenna with folded non-uniform meander line for 2.4/5 GHz WLAN bands

A low profile dual-band antenna for WLAN applications is proposed. It has the folded non-uniform meander line with the impedance bandwidth of 140 MHz at the 2.4 GHz band and 1500 MHz near 5 GHz with VSWR below 2, and an omnidirectional radiation pattern is obtained.     

Single layer printed monopole antenna for dual ISM-band operation

The ability of a single layer strip fed printed monopole, which has a serial-slot and an end-stepped feed-strip, to operate at dual Industrial, Scientific, and Medical-band (2.4 and 5.8 GHz bands) is demonstrated. This antenna combines omni-directional and broad bandwidth in an easy to fabricate structure. Experimental results indicate that the VSWR 2:1 bandwidths achieved were 8.2% and 18.2% at 2.45 GHz and 5.5 GHz. Effects of varying the serial-slot dimensions and the ground-plane size on the antenna performance are also described.     

Compact CPW-fed monopole antenna for 5 GHz wireless application

A compact and simple coplanar waveguide (CPW)-fed monopole antenna for 5 GHz wireless communication is proposed. By properly adjusting the lengths of both the monopole strip and the inverted L-shaped ground, the designed antenna, with, including ground plane, only 9/spl times/9.5 mm/sup 2/, can operate at the desired 5.2 or 5.8 GHz band. The electromagnetic coupling effect between the radiating strip and the ground on excitation of the resonant mode has been studied. Prototypes of the proposed antenna have been constructed and experimentally studied. Measured results show a -10 dB impedance bandwidth and an average antenna gain of 400 MHz and >6 dBi, respectively.     

A compact dual band planar branched monopole antenna for DCS/2.4-GHz WLAN applications

A compact dual band planar antenna for a digital communication system (DCS)/2.4-GHz WLAN application is presented. The two resonant modes of the proposed antenna are associated with various length of the monopoles, in which a longer arm contributes for the lower resonant frequency and a shorter arm for higher resonant frequency. The experimental results show that the designed antenna can provide excellent performance for DCS/2.4-GHz WLAN systems, including sufficiently wide frequency band, moderate gain, and nearly omnidirectional radiation coverage. The outcome of the experimental results along with the design criteria are presented in this letter.     

A 5-GHz LC VCO with digital AAC and AFBS for 2.4 GHz ZigBee transceiver applications

A 5 GHz LC VCO (voltage-controlled oscillator) with automatic amplitude control (AAC) and automatic frequency-band selection (AFBS) for 2.4 GHz ZigBee transceivers is presented. Instead of continuous feedback loop, an alternative amplitude calibration scheme is proposed in this paper to alleviate the deficiencies inherent in the conventional approach. It helps to keep the VCO at optimum amplitude to avoid saturation of the cross-coupled transistors and therefore stabilizes the phase noise performance over process, voltage and temperature variations. For the ZigBee application with 16 frequency channels, a coarse tuning loop is added in this work to implement the frequency-band selection using the AFBS mechanism. The VCO core and the digital AAC, AFBS modules have been fully integrated in a 2.4 GHz ZigBee transceiver which was fabricated in a 0.18 μm RF-CMOS technology. The current consumption is 4.7 mA at 4.85 GHz with 1.8 V power supply and a chip area of about 0.285 mm² is occupied. The VCO is capable of operating from 4.67 GHz to 5.18 GHz and the measured phase-noise level is –120 dBc/Hz at 1 MHz offset from a 4.85 GHz carrier. The tuning sensitivity K_VCO of the VCO is about 78 MHz/V with 0.9 V control voltage.