GHz WLAN Applications Research Articles

Compact tri-band bandpass filter with two closely frequency spaced passbands

A compact tri-band bandpass filter based on a novel six-mode resonator is proposed. The filter has three passbands centered at 2.45, 5.2, and 5.8 GHz for WLAN applications. Among them, two closely frequency-spaced passbands with a small center frequency ratio (1/1.11) are realized. The 3 dB bandwidth of the two passbands are 5.8 and 5.2%, which means they have equal absolute bandwidth. Source-load-coupling structure is adopted to enhance the high-isolation performance. And the filter has six transmission zeros, resulting in high-frequency selectivity. The passband frequencies and bandwidths of the filter can be controlled. The measured results are in good agreement with electromagnetic simulation. Its circuit only occupies 0.14 λg × 0.09 λg (11.2 mm × 7.1 mm), where λg is the guided wavelength at the lowest passband center frequency.

Design and Development of a Novel Miniaturized Fractal based 3-Bitloaded Line Phase Shifter

This paper proposes a new miniaturized 3-bit loaded line phase shifter for 2.45 GHz WLAN applications. The design use Koch fractal curves to reduce the size of the conventional loaded line phase shifter. The concept has been tested at 2.45 GHz on FR-4 dielectric material using microstrip technology. The phase error for the 8 phase states is not greater than 2.16degrees at the designed center frequency of 2.45 GHz, and the insertion loss for the 8 phase states is 2.63 dB±0.49dB over the operating bandwidth of 2.4 to 2.5 GHz. The performance can be further improved by using lower loss dielectric material.

Study and Design Evaluation of RF CMOS Oscillators

Objectives: To design and analyze the performance of CMOS RF Oscillator circuits at low supply voltage. Methods/Statistical Analysis: The Current Mode Logic (CML) based oscillator and LC oscillator is designed for 5GHz WLAN applications. The CML design adopts a DCO topology and the schematic layout is drawn using Microwind 2.7. The performance analysis is carried out using Intel Core2 Duo CPU E7400 @ 2.80 GHz processor. Advanced Design System 9.0 is used to implement schematics for analyzing the performances of proposed LC tank oscillator. Findings: The simulated results show that the tri-state inverter based DCO has 20 to 30% power reduction which is more than other conventional oscillator circuits. The CML inverter based DCO consumed more power than tri-state inverter because it used tail current transistor that provides always the static path from supply to ground. The theoretical phase noise is compared with simulated value of –95.19 dBc/Hz at same offset frequency. Application/Improvements: These designs produce a substantial improvement in performance and may be easily integrated with RF front-end blocks with minimal interface problems.

Design of compact size and tunable band pass filter for WLAN applications

Compact size and tunable band pass filter based on open-loop resonators is proposed. The proposed structure consists of dual-armed microstrip open-loop resonators. A second armed open-loop resonator, which acts as band rejection resonator, is connected directly to the input and output ports to achieve the desired band pass behaviour. The open-loop microstrip resonators are combined with four lumped capacitors to reduce the overall size of the proposed filter. The capacitors are inserted at places where maximum electric field is occurred in order to increase the effective capacitance and reduce the resonant frequency as well. The resonance frequency is translated from 6.75 to 5.3 GHz for WLAN applications. Consequently, the filter size will be more compact and the filter performance will be improved by enhancing the energy stored in the resonator. The proposed design using lumped capacitors represents a reduction in size of more than 35% when compared with conventional filter without using lumped capacitors. A good consistency is achieved between simulated and measured results.

Planar pattern reconfigurable antenna with eight switchable beams for WiMax and WLAN applications

A planar pattern reconfigurable antenna designed for IEEE 802.11 b/g standard 2.4 GHz WiMax and WLAN applications is presented. The design is realised using a uniform arrangement of eight switch-controlled tapered strips symmetrically placed around a central circular disc on the top layer of an FR4 board. The antenna has a compact circular structure with overall diameter of 0.64(0) in the free space for 2.4 GHz. To control the radiation pattern of the antenna, each of the tapered strips is connected to the ground via a PIN diode. Depending on the switching status of the eight PIN diodes, the tapered strips work in grounded or open-ended mode and thus the antenna offers eight switchable patterns. To validate the design, the antenna is prototyped and its performance is verified in a far-field anechoic chamber. The simulated and measured results prove the antenna's reconfigurability of the main beam in eight directions with 45 degrees steps in the azimuth plane and a vertical tilting angle of 36 degrees. Over the operating band 2.35-2.61 GHz, the antenna has a stable gain of around 4.5 dBi, and front-to-back ratio of more than 18 dB. Compared with recent designs, this antenna is more compact, has larger beam deflection off the boresight and more beam steering states.

Wide band SRR-inspired slot antenna with circular polarization for wireless application

In this paper, wideband slot antenna based on SRR-inspired structure with circular polarization in 2–3.8GHz for WLAN and WiMAX applications is designed. Metamaterial are highly attractive in antenna and microwave applications because of their negative permittivity and permeability. In this paper, SRR-inspired are employed to miniaturize and modify the antenna frequency and obtain CP (circular polarization). In order to achieve this CP characteristic by controlling the antenna current distribution, SRR-inspired loads are used and for improving axial ratio, a special shape of slot and corner truncation are implemented. The final antenna has bi-directional pattern with circular polarization and wideband in range of 2–3.8GHz for WLAN applications with gain of 2–3.5dBi. The size of prototype patch antenna is 40×40mm which is fabricated on FR-4 low cost substrate with εr=4.4 and thickness of 1.6mm. It is simulated by HFSS and CST microwave studio commercial full wave software’s. In addition, the designing process of the prototype antenna is explained completely and the experimental results are compared with the simulation one. The efficiency of final antenna is more than 90%.

DUAL BAND RECTANGULAR DIELECTRIC RESONATOR ANTENNA FOR WLAN APPLICATION

A compact dual band ring shape rectangular dielectric resonator antenna (RRDRA) to operate at 2.4 GHz and 5 GHZ WLAN application is proposed. In this design the dielectric resonator is fed by modified 50Ω trapezoidal micro strip line situated on top of the FR4 substrate. The simulated and measured impedance bandwidth achieved at 2.4 GHZ is 12.42% (2.3149-2.6132) and 12.9% (2.21-2.52) respectively; whilst for 5 GHZ at 13% (5.1795-5.8914) and 13.2% (5.08-5.81) for S11<-10 dB. And the gain of the proposed antenna is 4.9dBi and 5.9 dBi at 2.4 GHz 5GHZ respectively. Results are simulated using Ansoft High frequency structural simulator (HFSS) for the study of impedance bandwidth, return loss, radiation pattern and antenna gain. Furthermore the antenna has been fabricated and tested. The measured characteristics of the proposed antenna are in good agreement with the simulated results.

Design of compact multiband pattern diversity antenna for WiMax, LTE and WLAN applications

A compact multiband pattern diversity antenna for Multiple input multiple output (MIMO) applications is being proposed. The pattern diversity antenna is designed for 2.6 GHz LTE, 3.5/5.5 GHz WiMax, 3.3 GHz MIMO and 5.2 GHz WLAN applications for mobile devices. The compact size of the MIMO antenna (41.05 × 21.1 mm) is due to having compact individual monopole antennas each of dimension 17.5 × 10 mm. A T-shaped and inverted L-shaped stub in the ground plane reduces mutual coupling due to near field whereas slots introduced in the ground plane prevents current to flow through the common ground plane. The important characteristics of MIMO antenna like diversity gain and envelope correlation coefficient have also been presented. Measured and simulated radiation patterns presented show that the MIMO antenna proposed provide pattern diversity.

A compact omni‐directional circularly polarized antenna for WLAN applications

ABSTRACTA compact omni‐directional circularly polarized (CP) antenna is presented. The proposed CP antenna consists of a centrally fed circular patch and four curved branches which are printed on two substrates and the two substrates are connected by four metal pins. The center circular patch acts as a monopole and the four curved branches are employed as a current loop enabling the antenna radiates omni‐directional CP waves in azimuth plane. The antenna is designed at 2.4 GHz for WLAN application and printed on substrates with a compact size of 0.34λ0 × 0.34λ0 × 0.08λ0 (where λ0 is the wavelength in free space). To verify the design, the antenna is fabricated and measured. The measured results show that the antenna proposed in this article has an impedance bandwidth of about 10% (2.31‐2.55GHz) and 3dB axial ratio (AR) bandwidth of about 50% (1.9–3.2 GHz). The S‐parameters, axial ratios, radiation patterns, antenna gains, and antenna efficiencies are studied. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1011–1016, 2016

Hexa band mimo antenna with neutralization line for LTE mobile device application

ABSTRACTA hexa band MIMO antenna configured by two identical folded monopole antennas is proposed. The folded monopole antennas are connected by neutralization line. This antenna covers LTE 700, GSM 1800, GSM 1900, LTE 2300, LTE 2500 and 2.4 GHz WLAN applications. Good isolation characteristics and low envelope correlation coefficient is obtained. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1198–1204, 2016

Design and Fabrication of Microstrip Patch Antenna at 2.4 Ghz for WLAN Application using HFSS

Design and Fabrication of Microstrip Patch Antenna at 2.4 Ghz for WLAN Application using HFSS

Design of a Dual-Band Bidirectional Antenna Using Superellipse-Monopole-Fed Rectangular Ring for IEEE 802.11 a/b/g/n Applications

This paper presents the design of a dual-band bidirectional ring antenna fed by a superellipse surface probe for 2.4/5 GHz WLAN applications. The Method of Moments (MoM) with RWG basis function was utilized in the study and design processes. A prototype antenna was fabricated successfully with the advantages of simple and low-cost structure. The measured impedance bandwidth of 810 MHz (2.10–2.91 GHz) and 2.39 GHz (3.57–5.96 GHz) is achieved for the first and second band, respectively. The peak gains are also feasible, 4.67 dBi at 2.45 GHz and 7.83 dBi at 5.5 GHz, with bidirectional radiation patterns for both bands. From the experimental field tests, the proposed antenna was suitable for most applications in long and narrow communication sites in 2.4/5 GHz bands as desired. Also, the measured and calculated results were in good agreement.

Design of compact slot antenna based on split ring resonator for 2.45/5 GHz WLAN applications with circular polarization

In this article, compact slot antenna based on split ring resonator (SRR) with circular polarization (CP) for 2.4/5 GHz WLAN applications is noticed. Using metamaterial with both negative permittivity and permeability improves the antenna parameters. Thus, the prototype antenna is designed based on metamaterial SRRs to achieve CP and compact size. The final antenna has bi-directional pattern with CP and dual-band at 2.2–2.8 GHz for WLAN, Bluetooth application, and 5.2–7 GHz for IEEE WLAN protocol with gain 2.1 and 2.5 dBi, respectively. The size of prototype patch antenna is 40 × 40 mm. It is designed and fabricated on FR-4 low cost substrate with er = 4.4 and thickness of 1.6 mm. It is simulated by HFSS commercial full wave software. In addition, the experimental results are presented and compared here with simulation. The antenna efficiency is more than 90% for first band and more than 80% for second band and typically is more than 70% in 2–7 GHz. The antenna gain is simulated and compared with measurement and antenna gain is around 3–4.5 dBi. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:12–16, 2016

Dual Band E and L Shaped Antenna Design with Compact Radiator for 2.5/5.2/5.8 GHz WLAN Application- A Review

In this Paper is Present of Dual-band antenna with a compact radiator for 2.4/5.2/5.8 proposed by optimizing its resonant frequency, Bandwidth of operation and radiation frequency using genetic algorithm. The antenna consists L-shaped and E-shaped radiating element to generate two resonant mode for dual band operation. The above techniques have been successfully used in many applications on communication. Dual band antenna with compact radiator for 2.4/5.2/5.8 GHz WLAN application design and radiator size only width 8mm and length is 11.3 mm [1]. The antenna can we used for various application in field of communication. Genetic algorithm will be used to design the antenna and impedance matching network.

A 3–6 GHz Current Reused Noise Canceling Low Noise Amplifier for WLAN and WPAN Applications

A new ultra-wideband common gate low noise amplifier (LNA) for 3---6 GHz WLAN and WPAN applications is presented in which a current reused noise canceling structure utilized in the first stage not only provides a suitable noise performance, but also enhances the linearity characteristics of the LNA in a power efficient manner needed by WLAN/WPAN applications. The overall structure of the proposed LNA, consisting of three stages, namely input matching common gate stage with noise canceling, gain stage, and buffer one, is designed, laid out, and analyzed in 0.18 µm RF CMOS process. The LNA has a noise figure of 3.5---3.6 dB, a high and flat power gain of 20.27 ± 0.13 dB, and input and output losses of better than ?11 and ?14 dB, respectively, over the entire frequency band of 3---5 GHz, while these parameters are 3.5 dB, 20.75 ± 0.25 dB, ?15 and ?9 dB for the frequency band of 5---6 GHz, respectively. IIP2 and IIP3 of the proposed topology are equal to 25.9 and ?1.85 dBm, respectively, at 4 GHz frequency. The proposed LNA has 15.3 mW power dissipation from a 1.8 V supply.

A novel CB ACS-fed dual band antenna with truncated ground plane for 2.4/5 GHz WLAN application

A novel conductor backed asymmetric coplanar strip (CBACS) fed dual band antenna which is suitable for wireless local area network is presented in this paper. The proposed antenna is composed of inverted L-shaped exciting strip, a lateral ground plane and a modified truncated ground plane on the backside with overall dimension of about 25mm×17.5mm×1.6mm. The proposed design comprises monopole patch with asymmetric coplanar ground plane with conductor backing exhibit dual band of response with measured bandwidth of return loss ≤−10dB is 2.30–2.55GHz and 4.06–6.65GHz which cover all the WLAN bands (2.4/5.2/5.8GHz). The parametric studies indicate that operating frequencies and wider bandwidth are determined by the dimension of the ground plane at the top and bottom. The proposed antenna covers IEEE 802.11a/b/HYPERLAN-2/RFID band with good radiation characteristics. The measurement of proposed antenna that has been printed on an FR4 substrate with dielectric constant 4.4 yields good conformity between simulated results. The proposed structure is simulated using the method of moment based electromagnetic solver IE3D version 15.10.

Design of compact dual-band co-axially fed microstrip antenna for 2.4/5.2/5.8 GHz WLAN applications

This paper presents a single-layer co-axial fed compact rectangular microstrip antenna for 2.4/5.2/5.8 GHz WLAN applications. The antenna consists of four rectangular and one triangular slot inside the patch and one rectangular open-ended slot inside the ground plane. Measured impedance bandwidths (2.36–2.485 and 5.14–6.43 GHz) show that the antenna is suitable for the applications in WLAN IEEE 802.11b/g and IEEE 802.11a bands.

A 2.45-GHz W-level output power CMOS power amplifier with adaptive bias and integrated diode linearizer

A high-linearity CMOS power amplifier (PA) operating at 2.45GHz for WLAN applications with adaptive bias and an integrated diode linearizer is presented. The PA adopts adaptive bias scheme to adjust the gate bias voltage of power transistors by tracking the output power of the first diver amplifier for efficiency enhancement. Diode-connected MOS transistor is used to compensate the nonlinearity of input capacitance (Cgs) of power transistors for linearity improvement. The simulation results demonstrate a gain of 33.2dB, a maximum output power of 30.7dBm with 29% of peak power added efficiency (PAE) and −30dBc third-order intermodulation (IMD3) product at 26.4dBm output power, reaching to excellent tradeoffs between efficiency and linearity.

Compact Quasi-Elliptic Response Wideband Bandpass Filter With Four Transmission Zeros

This letter presents a novel quasi-elliptic response bandpass filter (BPF) with 3 dB fractional bandwidth of 39.8% for 2.4 GHz WLAN application. Four resonant modes from two stepped-impedance stub loaded shorted stepped-impedance resonators (SISLSSIRs) and one dual-mode shorted stub loaded stepped-impedance resonator (SSLSIR) can constitute an asynchronously tuned coupled-resonator circuit which support a wideband performance. Four transmission zeros (TZs), i.e., one TZ due to the mixed electric and magnetic coupling, one TZ due to the harmonic effects, and another two TZs owing to the cross-couplings, are realized on both sides of the passband, resulting in its quasi-elliptic response performance. The radial stubs and high-impedance open stubs are loaded at the middle position of SISLSSIRs to improve the in-band return loss of BPF. The fabricated filter has a compact size of $0.22\lambda_{\bf g}\times 0.22\lambda_{\bf g}$ and wide upper stopband from 2.62 to 7.69 GHz. Good agreement is shown between the simulated and measured results.

CIRCULAR POLARIZED TRANSPARENT ANTENNA FOR 5.8 GHZ WLAN APPLICATIONS

A novel design for a transparent circularly polarized circular slot antenna fed by a coplanarwaveguide (CPW) is presented in this paper. The circular polarization is achieved by introducing atapered split gap in the ring patch of the circular slot antenna in combination with unequal CPWground arms. The antenna is designed using AgHT-4 laminated on a 2 mm thick glass with a relativepermittivity of 7. The proposed antenna is designed to operate at 5.8 GHz for WLAN applications. Thetapered split gap and inequality in the lengths of the CPW ground arms contribute to a 3 dB axial ratiobandwidth from 5.4 to 6.2 GHz. The proposed antenna has been studied theoretically and fabricated.The measured results show that the proposed antenna has a gain of 0.92 dB at 5.8 GHz. Reflectioncoefficient (S11), axial ratio (AR), and radiation patterns are presented and briefly discussed.