Dual-band Filtenna Array for WLAN Applications

This paper presents the design and results of a dual-band antenna array integrated with bandpass filters for WLAN applications. The array is fed with a single 50 Ω port and consists of two radiating elements; thereby having a 1x2 array structure. The two bands of the antenna array correspond to the two WLAN bands of 2.4 GHz and 5.8 GHz. A standalone array has first been designed. Other than the two fundamental resonant frequencies, the standalone array exhibits spurious harmonics at various other frequencies. For the suppression of these harmonics, the array has been integrated with two bandpass filters, centered at 2.4 GHz and 5.8 GHz. The resulting filtenna array was simulated, fabricated and measured. Obtained simulation and measurement results agree well with each other and have been presented to validate the accuracy of the proposed structure. Measured return loss of the structure shows dual-bands at 2.4 GHz and 5.8 GHz of more than 30 dB each and also a successful suppression of the spurious harmonics of the antenna array has been achieved. Radiation patterns have also been simulated and measured and both results shown. The gain and efficiency have also been presented; with the values being 6.7 dBi and 70% for the 2.4 GHz band and 7.4 dBi and 81% for the 5.8 GHz band respectively.

Inkjet-Printed Filtennas with Triple Bandnotch

This paper presents the layout and results of a compact inkjet-printed filtenna operating at the S-band, ISM and UWB frequencies. The filtenna has a wide passband and, alongside, rejects WiMAX 3.5 GHz, WLAN 5.8 GHz and ITU service 8.2 GHz bands. The filtenna is simulated, printed using silver nanoparticle ink on flexible Kapton substrate and measured. Obtained simulation and measurement results agree well with each other. Measured return loss of the filtenna is more than 10 dB for 1.6–10.85 GHz and triple bandnotch, measuring at an average of 1.87 dB, are present at the unwanted bands. Radiation patterns, as well as the gain and efficiency of the filtenna have also been presented; with the average values being 3.4 dBi and 90 % respectively for the passband and averaging at −1.0 dBi and 22 % respectively for the three rejected bands.

Highly linear reconfigurable UWB filters with independently controlled dual bandnotch

This letter proposes a high-linearity reconfigurable lower ultra-wideband (3.1–5.25 GHz) filter with independently controlled dual bandnotch at WiMAX 3.5 GHz band and satellite communication systems 4.2 GHz band. Reconfigurability has been achieved by the implementation of Graphene based switches (simulation only) and PIN diodes (measurements). The simulation and measurement results in OFF state show an entire bandpass response from 3.1 GHz to 5.25 GHz and with a very low insertion loss. In ON state, the results show that sharp rejections at 3.5 GHz and 4.2 GHz are achieved, with a low passband insertion loss. The two bandnotch operate independently of each other; thus allowing to control the behaviour of the required bandnotch. The third order intermodulation products were also measured in OFF and ON states and the linearity results have been presented. The filter is able to achieve a high performance with good linearity and no significant loss.

The Impact of Uncertainty Shocks under Measurement Error: A Proxy SVAR approach

A growing literature considers the impact of uncertainty using SVAR models that include proxies for uncertainty shocks as endogenous variables. In this paper we consider the impact of measurement error in these proxies on the estimated impulse responses. We show via a Monte-Carlo experiment that measurement error can result in attenuation bias in impulse responses. In contrast, the proxy SVAR that uses the uncertainty shock proxy as an instrument does not su¤er from this bias. Applying this latter method to the Bloom (2009) data-set results in impulse responses to uncertainty shocks that are larger in magnitude and more persistent than those obtained from a recursive SVAR.