Damir Zayniyev

Microstrip filters and diplexers for WiMAX applications

In this paper microstrip diplexers for WiMAX was designed using novel super compact microstrip pseudo-interdigital quasi-elliptical bandpass filters. Diplexer is for separation of first and second channels of IEEE 802.16e standard, which are 2.3-2.7 GHz and 3.3-3.9 GHz.

Dual-band microstrip antenna filter for wireless communications

Integration of antenna and bandpass filter in one module is one of the ways to achieve miniaturisation and improved performance of microwave front ends. In dual or multiband systems the integration of multiband antennas with dual-band filter can be used for suppression of unwanted harmonics of antenna and improvement of reflection loss and selectivity of antenna. As most of modern systems use two or more frequency bands, for example WLAN standard IEEE 802.11 operating at 2.4–2.45 GHz and 5.15–5.85 GHz and WiMAX IEEE 802.16 standard operating at 2.3–2.7 GHz, 3.3–3.9 GHz and 5.15–5.85 GHz bands, the implementation of dual-band antenna integrated with band select filters becomes more practical solution then usage of diversity antenna. This approach, together with novel architecture of dual-band front end, was presented in [1].

Compact microstrip pseudo-interdigital stepped impedance bandpass filters with improved stopband performance

In this paper we present design of a compact microstrip pseudo-interdigital stepped impedance bandpass filter with improved stopband performance. Stepped-impedance resonators are used to maximise the ratio between higher order and fundamental resonances. The improved stopband performance is realized using additional spur line and open-stub sections used for creation of transmission zeros. Total size of the filter is 30.1×7.2 mm. The stopband extension up to 5.7f0 has been achieved.

Microstrip three-port 4-channel multiplexers using dual-band bandpass filters for wireless applications

This paper presents a compact microstrip three-port 4-channel multiplexer using dual-band bandpass filters with good transmission and reflection characteristics on each channel. Proposed multiplexer configuration can be used for design of very compact multiplexer for broadband wireless applications using super compact microstrip pseudo-interdigital quasi-elliptical bandpass filters with or without stepped impedance resonators. The size of the proposed circuit is reduced. The improvement of the performance of multiplexer through introduction of additional transmission zeros is under investigation.

Microstrip patch antennas with harmonic rejection using composite right-left handed transmission lines

In this paper a 2.4 GHz patch antenna with improved performance was designed, using harmonic tuner with Composite Right/Left-handed (CRLH) transmission lines. Composite Right-Left Handed (CRLH) transmission line was modelled as a periodic structure with infinitesimal unit cells. The unit cell consists of a RH series inductance LR and shunt capacitance CR (conventional transmission line) and LH series capacitance CL and shunt inductance LL.

Compact microstrip dual-band pseudo-interdigital stepped impedance bandpass filters for wireless applications

A novel compact microstrip dual-band pseudo-interdigital stepped impedance bandpass filter has been proposed. Compactness has been achieved using the hybrid interdigital and hairpin lines. The implementation of stepped impedance has been used to tune the first spurious resonance of filter to make it appear at 2.4f0. The proposed microstrip dual band bandpass filter, having a size of 8.70 × 29.00 mm at a center frequency of 2 GHz for channel 1 and 4.8 GHz for channel 2 has been designed, fabricated and tested. The simulated and experimental results have been presented to validate the argument. The filter is easy to manufacture and the results are easily reproducible.