Modern Wi-Fi receivers require strict design specifications including low noise figure, high selectivity, high power gain, low input reflected power, high linearity, and good stability. This article is devoted to present a design approach for a low noise amplifier integrated with a band pass filter to operate in the Wi-Fi frequency band from 2.25 GHz to 2.65 GHz. The low noise amplifier has been designed to satisfy both low noise figure and reduced input return loss using a commercial low cost SiGe hetero-junction bipolar transistor (HBT). On the other hand, the band pass filter is synthesized using three directly-coupled microstrip resonators. The cascaded circuit has been fabricated on Rogers RO4350B substrate and tested experimentally. The measured results show that the power gain of the circuit is about 10.5 dB at the center frequency (2.45 GHz), input return loss is less than -14 dB, and output return loss is less than -12 dB within the desired Wi-Fi band. It has been confirmed that the circuit gives both low noise figure and reduced input reflection coefficient with good stability at the desired band using new structure of a high selectivity bandpass filter to remove the out of band noise. 

In this paper a novel and flexible technique to design a dual band antenna for desired frequency bands is proposed. The two bands are achieved using a single straight slit present in ground plane, inclined at 450 with respect to axis of the radiating patch. An extensive parametric analysis is carried out at 5.8 GHz to study the effect of inclined slit on the performance of radiating patch for a range of dielectric substrates with dielectric constant ranging from 2.2 to 6.5 for thickness of 1 mm, 1.6 mm and 2 mm. The verification of this novel technique is attained through the design of a dual band antenna to cover 1.8 GHz and 2.4 GHz bands. The simulated results are in close agreement with the measured results. The paper also covers criteria to select dielectric material and its thickness for a desired frequency ratio of the two bands. The proposed technique successfully achieves a size reduction of the radiating patch by 57.48%. The primary merit of the proposed methodology is that it allows easy replication across diverse wireless applications. 

A novel fractal antenna is designed by using fractal geometrical structures. It is constructed with the principles of both Koch snowflake and Minkowski curve algorithms with asymmetric coplanar strip –fed antenna. The upper portion of the rectangular is made of Koch Sowflake and its lower portion is Minkowski structure. Both structures combined together in one patch to improve the bandwidth of the antenna. This novel antenna adapted four iterations, which results in an optimum output. It has wide bandwidth of 1.45GHz and can be used for high speed Wi-Fi applications. The substrate material selected for this novel antenna is FR4. The antenna is compact in size with dimension 21*21mm2. The return loss of the antenna is 30.5 dB at 4.5 GHz and its gain and efficiency are 7.2 dBi and 94.40% respectively. The novel antenna, which gives optimum result, is fabricated, and its parameters are analysed. The resultant antenna was compact size and low profile.