Azman Ahmad

This paper presents the design of dual-band low noise amplifier (LNA) for WLAN IEEE 802.11b/g/a/n wireless applications. A new technique using a cascaded LNA, notch filter and T network impedance matching is proposed. A fully integrated dual band LNA was designed using GaAs pHEMT transistors to increase and improve the gain and noise figure (NF) effectively. The LNA was matched concurrently at the two frequency bands by matching the input and output networks without switching techniques. The post layout simulation shows the power gain |S21| of 33.845 dB and 20.000 dB and NF of 0.946 dB and 0.493 dB for center frequency of 2.4 GHz and 5.75 GHz. The supply voltage for LNA is 2V.

A new type of dual-band bandpass filter (BPF) using microstrip line is presented in this paper. The proposed design consists of coupled-lined filter, butterfly radial stub and 45° miltered bending with new structure called Dual Band Bell Shaped Filter (DBBSF). The proposed DBBSF consists of two fundamental resonant modes with the bandwidth resonant characteristic has been investigated using ADS software. The bandwidths are achieved through optimising the butterfly radial stub for high frequency passband. In addition, 45° miltered bend improved its insertion loss and return loss level in good agreement. To validate the design and analysis, the DBBSF were fabricated and measured. The DBBSF leads to reduction of overall circuit size which is 2.5mm x 2.5mm. A dual-band response BPF that operates at 2.4 GHz and 5.75 GHz is designed and implement for wireless applications.

This paper presents the design and analysis of a dual-band low noise amplifier (LNA) at 2.4 GHz and 5.75 GHz for IEEE 802.11 a/b/g applications. This LNA proposed current-reused topology and presented new Hi-Pass and Lo-Pass matching technique network at the two stage common-source transistor. The LNA used GaAs HEMT transistor to improve the gain and noise figure (NF) matched concurrently at the two frequency bands. The simulation results showed a high gain |S21| of 36.093 dB and 23.152 dB and low NF of 0.735 dB and 0.530 dB for center frequency of 2.4 GHz and 5.75 GHz. The supply voltage for LNA is 2V. Simulation of the design was performed with the Advanced Design System (ADS) software.

A new approach for designing a narrow dual bandpass filter (BPF) using microstrip coupled line filter with new shaped of `bell' structure resonator is presented in this paper. The proposed BPF consists of two fundamental resonant modes and the resonant characteristic has been investigated using Advanced Design System (ADS) software. To validate the design and analysis, the filter were fabricated and measured. It shown that the simulated and measured performances are in good agreement. A dual band frequency which operates at 2.4 GHz and 5.75 GHz is designed and implement for RF front end receiver systems.

This paper presents the design and analysis of a dual-band low noise amplifier (LNA) at 2.4 GHz and 5.75 GHz for IEEE 802.11 a/b/g applications. This LNA proposed current-reused topology and presented new Hi-Pass and Lo-Pass matching technique network at the two stage common-source transistor. The LNA used GaAs HEMT transistor to improve the gain and noise figure (NF) matched concurrently at the two frequency bands. The simulation results showed a high gain |S21| of 36.093 dB and 23.152 dB and low NF of 0.735 dB and 0.530 dB for center frequency of 2.4 GHz and 5.75 GHz. The supply voltage for LNA is 2V. Simulation of the design was performed with the Advanced Design System (ADS) software.

This paper presents the design of dual-band low noise amplifier (LNA) for WLAN IEEE 802.11b/g/a/n wireless applications. A new technique using a cascaded LNA, notch filter and T network impedance matching is proposed. A fully integrated dual band LNA was designed using GaAs pHEMT transistors to increase and improve the gain and noise figure (NF) effectively. The LNA was matched concurrently at the two frequency bands by matching the input and output networks without switching techniques. The post layout simulation shows the power gain |S21| of 33.845 dB and 20.000 dB and NF of 0.946 dB and 0.493 dB for center frequency of 2.4 GHz and 5.75 GHz. The supply voltage for LNA is 2V.

A new approach for designing a diplexer for dual-band bandpass filter (BPF) using a parallel coupled microstrip line filter is presented in this paper. The proposed diplexer consists of two fundamental resonant modes and the resonant characteristics has been investigated using Advanced Design System (ADS) 2011 software. To validate the design and analysis, two band-pass BPF were fabricated and measured. It shown that the measured and simulated performance are in good agreement. A dual-band response BPF that operates at 2.4 GHz and 5.75 GHz is designed and implement for IEEE 802.11a/b/g applications.

This paper presents the design of triple stages cascoded low noise amplifier using an inductive drain feedback (IDF) technique which operates at frequency 5.8 GHz for WiMAX application. The triple stages cascoded LNA was designed using the inductive drain feedback, inductive generation to the source, and the T-network at the input and output terminal as a matching technique. This LNA produced a gain (S21) of 79.16 dB and the noise figure (NF) of 0.71 dB. The output reflection (S22), input reflection (S11) and return loss (S12) are -12.56, -11.96 dB and -100.22 dB respectively. The measured 3dB bandwidth of 1.76 GHz has been achieved. The input sensitivity is -92 dBm exceeded the standards required by the IEEE 802.16. The amplifier it is implemented using superHEMT FHX76LP transistor devices. The designed circuit is simulated with Ansoft Designer SV.

A 0.7 dB (min.) low noise figure PHEMT LNA at 5.8 GHz using an inductive drain feedback that is applicable to the WiMAX 802.16 standard. The amplifier uses FHX76LP superHEMT low noise FET. The Ansoft Designer was used during the design process. The low noise amplifier (LNA) produced the forward transfer gain (S21) of 43.74 dB. The return loss (S12), input reflection (S11) and output reflection (S22) are -52.41 dB, -10.60 dB, -18.22 dB respectively. The measured 3dB bandwidth of 1.24 GHz has been achieved. The input sensitivity is -80 dBm compliant the standards required by IEEE 802.16.

This research present a design of a higher  gain (66.38dB) for PHEMT LNA  using an inductive drain feedback technique for wireless application at 5.8GHz. The amplifier it is implemented using PHEMT FHX76LP transistor devices.  The designed circuit is simulated with  Ansoft Designer SV.  The LNA was designed using  T-network as a matching technique was used at the input and output terminal,  inductive generation to the source and an inductive drain feedback. The  low noise amplifier (LNA) using lumped-component provides a noise figure 0.64 dB and a gain (S21) of 68.94 dB. The output reflection (S22), input reflection (S11) and return loss (S12) are -17.37 dB, -15.77 dB and -88.39 dB respectively. The measurement shows the  stability was at  4.54 and 3-dB bandwidth of 1.72 GHz. While, the  low noise amplifier (LNA) using  Murata manufactured component provides a noise figure 0.60 dB and a gain (S21) of 66.38 dB. The output reflection (S22), input reflection (S11) and return loss (S12) are -13.88 dB, -12.41 dB and -89.90 dB respectively. The measurement shows the  stability was at  6.81 and 3-dB bandwidth of 1.70 GHz. The input sensitivity more than -80 dBm  exceeded the standards required by IEEE 802.16.