a compact and sharp-rejection ultra-wideband (uwb) microstrip bandpass filter (bpf) is presented. the proposed filter is constructed with multiple-mode resonator (mmr) and split ring resonator (srr). moreover, proposed structure consists of two doublets parallel coupling gaps at each side of a microstrip ring. in comparison with some other filters, this structure shows a significantly wider pas...

A fourth-degree Substrate Integrated Waveguide (SIW) crossed coupled band pass filter for WLAN band is designed by using a new negative coupling structure. It consists of two U shape microstrip lines on top and bottom planes with via holes at the center of them. This paper investigates the phase characteristics of negative and positive coupling structures and their effects. The design, fabricat...

Wireless communication has been developed rapidly in the past decades and it already has a great impact on human life. In the field of wireless communications, antennas play a vitally important role. In the late 1970s, there was rapid development in the field of microstrip patch antenna technology. In early 1980s, antenna elements and arrays were developed in terms of design and modeling. Due t...

An ultra-wideband (UWB) microstrip filter with a fractional bandwidth (FBW) of more than 100% is designed and demonstrated. This UWB microstrip-filter design is based on a circuit model for an optimum short-circuited stub transmission-line filter whose unit Figure 4 Reflection coefficient of the ultra-thin absorber: (a) simulated reflection coefficient; (b) measured reflection coefficient; (c) ...

a fourth-degree substrate integrated waveguide (siw) crossed coupled band pass filter for wlan band is designed by using a new negative coupling structure. it consists of two u shape microstrip lines on top and bottom planes with via holes at the center of them. this paper investigates the phase characteristics of negative and positive coupling structures and their effects. the design, fabricat...

A miniaturized self-matched negative group delay (NGD) microwave circuit without the need for external matching networks is proposed. The NGD circuit is based on a modified parallel-type RLC resonator, in which lumped elements (capacitors and inductors) are implemented by microstrip gaps and high-impedance and short-circuited microstrip lines. To verify the design concept, an NGD circuit with t...

In this paper, a compact microstrip diplexer is proposed for Wimax and DCS applications at 2.5 GHz and 1710-1880 MHz respectively. The microstrip diplexer consists of two band-pass filters operating at different frequency bands and a coupledjunction. Each filter is formed by a meander-line resonator and two Input/Output feed lines. The frequency response of each filter can be easily controlled ...

In this paper, we present a new method for the design of multi-band microstrip filters. The proposed design method is based on Differential Evolution (DE) with strategy adaptation. This selfadaptive DE (SaDE) uses previous experience in both trial vector generation strategies and control parameter tuning. We apply this algorithm to two design cases of dual and tri-band filters for WiFi and WiMa...

This paper reports two techniques for optimizing harmonic termination in power amplifiers. In the jirst technique, the active antenna approach, the antenna element acts as radiator and as part of the output tuning circuit. The second method, based on photonic band-gap (PBG) structure, incorporates a periodic harmonic tuning structure for microstrip lines. In this structure, a periodic 2-D patte...

In this paper a new design of a broadband microwave power limiter is presented and validated into simulation by using ADS software (Advanced Design System) from Agilent technologies. The final circuit is built on microstrip lines by using identical Zero Bias Schottky diodes. The power limiter is designed by Associating 3 stages Schottky diodes. The obtained simulation results permit to validate...