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This article proposes a reconfigurable low-profile monopolar antenna with triple-band independent tuning capability. The antenna is based on the concept of a center-fed patch with shortings to achieve omnidirectional radiation patterns. Instead of using vias, varactor-loaded stubs are utilized to create reconfigurable equivalent shorting points. The triple bands can be achieved by using three sets of stubs. This configuration results in three magnetic current loops that spatially overlap at different independently tunable frequencies. Measurement results show that the design obtains three independent tunable frequencies centered at 2.51, 3.56, and 4.62 GHz with -10 dB relative tuning ranges of 22.8%, 22.8%, and 16.7%, respectively. The antenna radiates omnidirectionally with vertical polarization in the three sweeping bands. The proposed concept can be extended to a larger number of bands by adding sets of stubs with considerations of coupling and impedance matching.

In this paper, the microstrip planar fourtear antenna that operate at frequency range 2300 – 2500 MHz was investigated, Some applications suitable to operate in this frequency are WiMAX at 2.3 and 2.5 GHz and WLAN at 2.4 GHz. Simulations performed with the aid of Finite Element Emthod (FEM) based software which can calculte and comply the appropriate design to be able to operate at the desired working frequency. The analyzed parameters include : SWR, impedance, return loss, radiation patterns, gain, and polarization. From the measurement, bandwidth obtained is equal to 7.69% in the frequency range of 2318,250-2500 MHz in VSWR < 2. Radiation pattern measurement was unidirectional and the polarization was elliptical.

Low-profile monopole antennas using via and via-less shorting methods are compared in terms of performance. Stubs and complimentary split ring resonators are used as via-less shorting to replace classical vertical pins. All designs use the same substrate and are optimized to operate at the same frequency. Measurement results from fabricated prototypes show good agreement with simulations.

Synthetic Aperture Radar (SAR) is radar technology for remote sensing which transmits electromagnetic pulse to earth where the pulse is reflected back to SAR and received by antenna receiver. The received signal is very low, it should be amplified by Low Noise Amplifier (LNA). To satisfy the SAR system, this paper propose to design a double stage LNA which operate at 1.27 GHz. In the design process, it used active component BJT Transistor of BFP 640 for the both stage. While to achieve the impedance matching condition is deployed on an FR4 substrate which has 4.6 of dielectric permittivity. The Advanced Design System (ADS) is applied to determine gain, voltage standing wave ratio (VSWR), and noise figure (NF) as LNA characterization. The simulation results at 1.27 GHz recorded 42.10 dB of gain, 1.87 of NF, while input VSWR and output VSWR are 1.15 and 1.25 respectively.

Microstrip antenna has a small gain, bandwidth and efficiency. To overcome those weaknesses, this paper focused on a design of multilayer parasitic substrate for enhancing antenna gain. The distance between first layer parasitic and second layer parasitic had been optimized to maximize electromagnetic coupling and improve antenna main lobe. The microstrip antenna had been fabricated using FR-4 epoxy substrate with 4.2 dielectric constant. Measured antenna acquires unidirectional radiation pattern, 70° beamwidth azimuth, 2.333 GHz–2.377 GHz of operating frequency at VSWR ≤ 2, 44 MHz of bandwidth, and Gain = 4.64 dB. The dimension of realized antenna was 151.5 mm × 151.5 mm. This antenna was purposed to work for LTE band 40 at 2.35 GHz.

A four port diversity microstrip patch antennas for WLAN was designed, working in the 5.180 to 5.220 GHz frequency. Port diversity was carried out by changing the orientation of the port as of 90° between each consecutive port to reduce mutual coupling and reduce overall dimensions of the antenna. Dimension of realized antenna was 49.48 mm × 49.48 mm. All antenna element has VSWR ≤ 1.5 and mutual coupling ≤ −20 dB. Bandwidth of the antenna 1 to 4 was 92, 96, 68, and 83 MHz respectively. The resulting gain antenna 1 to 4 was 3.306, 3.428, 3.38, and 3.315 dBi respectively. The antenna had unidirectional radiation pattern with elliptical polarization.

This paper studies the design of two stage microwave low noise amplifier (LNA) for coastal radar application at S-band operation. The cascade amplifier configuration and double stub matching networks are applied in this design which is aimed to obtain high gain with minimum reflected RF power. The first stage uses E-pHEMT GaAs FET of ATF-551M4 type and the second one uses RF transistor of BFP740FESD type as an active device, respectively. The duroid substrate of 5880 type as a stub of microstrip line is deployed to achieve matching impedance network. This work uses the Agilent Design System (ADS) software to optimize the performance of LNA circuit design. The derived LNA characteristic at frequency 3 GHz are Gain = 30.87 dB, Noise Figure (NF) = 1.18 dB, VSWR input = 1.05 and VSWR output = 1.18, respectively.

In this paper, a modified fractal sierpinski patch antenna suitable for multiband wireless application is proposed. Various heights of a triangle component in sierpinski antenna are compared to achieve the desired resonant frequencies and then a coplanar wave guide feed is used to achieve more multiband resonant frequencies within 0-7 GHz frequency range. Return loss characteristics suggest that the antenna is suitable for WLAN, Wimax and also GSM bands for VSWR

A novel method for eliminating noise from a noised speech signal in order to improve its quality using combined power spectral subtraction and multi-layer perceptron network is presented in this paper. Firstly, the contaminated speech signal was processed by spectral subtraction to enhance the clean speech signal. Then, the signal was processed by a neural network using the spectral subtraction parameters and result of estimated speech signal in order to improve its signal quality and intelligibility. The artificial neural network used was multi-layer perceptron network consisted of three layers with six input and one output. The neural network was trained with three speech signals contaminated with two level white gaussian noises in SNR including 0 dB and 30dB. The designed speech enhancement was examined with ten noised speech signals. Based on the experiments, the improvement of signal quality SNR was up to 7 dB when the signal quality input was 0dB. Then, based on the PESQ score, the proposed method can improve up to 0.4 from its origin value. Those experiment results show that the proposed method is capable to improve both the signal quality and intelligibility better than the original power spectral subtraction.

Tapered slot vivaldi antenna is an antenna type that has a very wide bandwidth. With that performance, tapered slot vivaldi antenna can cause interference if it is applied on a weather radar that requires a fairly narrow bandwidth only. Therefore, this paper will discuss the design and simulation to narrow bandwidth of the tapered slot vivaldi antenna in order to provide good performance when applied for weather radar that operates at 9.4 GHz. Design and simulation uses CST Microwave Studio software by varying its dimension. From simulation has been obtained vivaldi tapered slot antenna bandwidth narrowed down to 13% at frequency operation, while other antenna parameters still meet to the weather radar antenna requirement.

In this paper Radio Frequency Identification (RFID) antenna that operates in millimeter wave at 35 GHz has been proposed. At millimeter wave, higher data rate up to gigabit is proven to be possible because the signal at this band could create pencil beam with higher gain. Voltage Standing Wave Ratio (VSWR) of fabricated antenna at 35 GHz was 1.083, with bandwidth of 200 MHz for VSWR

In this paper, an X Band antenna for ground surveillance manpack radar was designed with 15 × 38 cm dimension using RT/Duroid 5880 substrate. The array consisted of 64 patches antenna with a carved slit to obtain a horizontal polarization. The gap between antenna feed were evaluated and the results are that that antenna gain and side lobe level will decrease as the gap became larger. This design has 200 MHz bandwidth with gain of 25.2 dB and side lobe level of −22.7 dB.

This paper demonstrates the concept of a polarization-reconfigurable omnidirectional antenna. The proposed antenna is based on a circular patch surrounded with PIN diodes controlled arms. Polarization-reconfigurability is obtained by switching the state of the PIN diodes, enabling the antenna to radiate in two different modes of polarization, namely linear and circular. From the simulation results, the linearly-polarized radiation occurs in the frequency of 5.20–5.38 GHz, while from 5.29 to 5.45 GHz the antenna radiates in a circularly-polarized manner. Additionally, stable omnidirectional patterns are obtained in both polarization modes.