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A rectangular waveguide bandpass filter for $Q$ -band with simple fabrication is proposed in this letter. The design is based on the use of the first passband replica of commensurate-line stepped-impedance structures and achieves the suppression of their inherent low-pass response. In order to do it, the filter is implemented by rectangular waveguide sections with different widths and heights that can be analytically calculated. The technique is validated by a ninth-order Chebyshev filter with passband between 40 and 43 GHz and fabrication yield equal to 84% for a manufacturing error of $\pm 20~\mu \text{m}$. The measured results of the prototype fabricated with computer numerical control (CNC) milling are in good agreement with the simulated ones. [ABSTRACT FROM AUTHOR]

In this article, an efficient algorithm implementation is presented for the synthesis of microwave circuits with arbitrary frequency responses. A comprehensive theory development is included starting from the formalism of the coupled-mode theory to obtain an exact series solution for the inverse scattering problem. A final algorithm in pseudocode is available in this article together with graphical diagrams to provide a straightforward implementation for the interested reader showing its feasibility for parallel computing. As an example, a design of a matched filter for broadband communications is presented along with the operational insight of the applied method, the influence of the auxiliary parameters, and the comparison between target frequency responses, simulations, and measurements. This application in microstrip technology is enclosed as an instance of the versatility of our synthesis technique and the accuracy of the presented algorithm. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. [ABSTRACT FROM AUTHOR]

In this article, a design method for high-power low-pass filters with wide rejection band is proposed for rectangular waveguide technology. The new filters consist of a classical high-power E-plane corrugated low-pass filter that is cascaded with a quasi-periodic structure tuned to reject its undesired intrinsic spurious passbands. The new design technique presented here does not impose any limitations on the gap aperture of the original E-plane corrugated filter. This allows the minimum gap of the corrugated filter to be kept wide which, along with the smoothness and the wide gap of the quasi-periodic structure itself, enables high-power TE10 mode operation in the whole structure as the spurious passbands are suppressed. An example will be given in Ku-band. The resulting prototype will have several kilowatts handling capability and the spurious passbands will be suppressed up to the third harmonic (around 40 GHz). The new design method may have an important practical impact in the design of the low-pass filter required at the output of the satellite output multiplexers. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1724–1728, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25331 [ABSTRACT FROM AUTHOR]

Combining an electromagnetic band-gap structure (EBG) and squared split-ring resonators (SSRRs) in a planar microstrip line circuit, negative values of electric permittivity and magnetic permeability can be obtained. This phenomenon arises thanks to the negative permeability of the SSRR particles when they operate in the vicinity of their quasi-static resonance frequency, and the negative permittivity due to the behavior of the EBG structure within the rejected frequency band. Therefore, a novel approach is presented in this article to synthesize a left-handed media in microstrip technology. Full wave simulation results as well as measurement results from a fabricated prototype confirm the left-handed behavior of the interaction. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2689–2692, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22841 [ABSTRACT FROM AUTHOR]

The ability of planar left-handed metamaterials (LHMs) based on split-ring resonators (SRRs) to radiate backwards in a certain frequency range, as predicted by theory, is demonstrated. A comparison between an LHM and a negative permeability metamaterial in terms of the experimental backward and forward radiation cones (which are related to their dispersion diagrams) is carried out. The results of this work open the possibility to use SRRs as miniaturised and flexible radiating elements for antennas and arrays in wireless communication applications. [ABSTRACT FROM AUTHOR]

By using a recently proposed approach to synthesize 1D metamaterials in planar circuit technology, compatible with fully planar fabrication techniques, a novel backward coupler has been designed and fabricated. It has been implemented in microstrip technology by means of complementary split-ring resonators (CSRRs), etched in the ground plane, and series capacitive gaps. This way, we obtain the necessary left-handed properties for reversing the forward coupling (typical of co-directional coupled-line couplers) into backward coupling. The simulation as well as measurement results confirm the enhanced properties of the proposed couplers. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1205–1209, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21579 [ABSTRACT FROM AUTHOR]

In this paper, the potential use of complementary split-ring resonators (CSRRs) to design very compact waveguide filters, by etching a CSRR in the center of a metallic sheet, is demonstrated. This original layout reduces the dimensions of the well-known resonant-cavity waveguide filters coupled by irises. This has been made feasible due to the self-resonance property of the CSRR. Thus, it is possible to design waveguide filters with lengths equal to the thickness of a metallic sheet. Consequently, this technique paves the way for the design of miniaturized waveguide filters, in contrast to conventional waveguide filters, based on bulk resonators. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 88–92, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20909 [ABSTRACT FROM AUTHOR]

In this paper, microstrip lines magnetically coupled to split-ring resonators (SRRs) are compared to electromagnetic bandgap (EBG) microstrip lines in terms of their stop-band performance and dimensions. In both types of transmission lines, signal propagation is inhibited in a certain frequency band. For EBG microstrip lines, the central frequency of such a forbidden band is determined by the period of the structure, whereas in SRR-based microstrip lines the position of the frequency gap depends on the quasi-static resonant frequency of the rings. The main relevant contribution of this paper is to provide a tuning procedure to control the gap width in SRR microstrip lines, and to show that by using SRRs, device dimensions are much smaller than those required by EBGs in order to obtain similar stop-band performance. This has been demonstrated by full-wave electromagnetic simulations and experimentally verified from the characterization of two fabricated microstrip lines: one with rectangular SRRs etched on the upper substrate side, and the other with a periodic perturbation of strip width. For similar rejection and 1-GHz gap width centered at 4.5 GHz, it has been found that the SRR microstrip line is five times shorter. In addition, no ripple is appreciable in the allowed band for the SRR-based structure, whereas due to dispersion, certain mismatch is expected in the EBG prototype. Due to the high-frequency selectivity, controllable gap width, and small dimensions, it is believed that SRR coupled to planar transmission lines can have an actual impact on the design of stop-band filters compatible with planar technology, and can be an alternative to present solutions based on distributed approaches or EBG. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 376–379, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20640 [ABSTRACT FROM AUTHOR]

In this work, we study the reflection properties of coplanar waveguides (CPW) periodically loaded with shunt connected capacitances and periodically perturbed by varying the slot width. These structures are of interest because the low pass frequency response with spurious frequency bands, inherent to the presence of capacitors, can be improved. This is achieved through the attenuation of frequencies parasitics that is obtained by the introduction of slot width modulation. Both sinusoidal and square wave patterns are considered and the effects of the relative position of reactive elements with regard to the perturbation geometry is analysed. According to coupled model theory, the central frequencies of the rejected bands in periodic transmission media are given by the spectrum of the perturbation function. However, it is demonstrated that, due to the presence of capacitors, multiple spurious bands can be simultaneously suppressed even in the case of a singly tuned (sinusoidal) perturbation geometry. This result points out that the frequency selective behavior associated to the presence of slot width modulation can not be interpreted in the framework of coupled mode theory, since the rejection of spurious bands in periodic loaded CPWs is not merely given by the spectrum of the perturbation geometry. [ABSTRACT FROM AUTHOR]

A new periodic loaded coplanar waveguide (CPW) low-pass filter with very sharp cutoff has been designed and fabricated. The device consists of a CPW structure with T-shaped periodic patterns on both the central strip and ground planes. With such a design, capacitive coupling is added between the signal strip and ground planes at periodic positions, resulting in a filtering action and slow-wave effect. In addition to a sharp cutoff, the device exhibits very low insertion loss in the pass band, wide rejection bandwidth, and simple design and fabrication. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 190–193, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11011 [ABSTRACT FROM AUTHOR]

The influence of the window shape in the frequency response of electromagnetic crystals (ECs), made by etching a sinusoidal continuous pattern of constant period and variable amplitude on the ground plane of a microstrip line, is studied in terms of rejection level, bandwidth, side-lobe level, and stopband abruptness. A new parameter, the equivalent number of periods, is found to be a good estimate of the increase in length needed to maintain the rejection level and bandwidth of the uniform structure, while reducing the secondary lobes by applying a window. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 37–40, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10663 [ABSTRACT FROM AUTHOR]

Microwave filters in microstrip technology have been designed by taking advantage of metal patterning of the front and back-side planes. It is shown that such an approach with drilled holes in the ground plane for the high impedance sections permits one to alleviate some of the drawbacks associated with uniplanar impedance modulated filters with high geometric aspect ratios. Prototypes for the S and C-bands were fabricated by conventional low-cost printed circuit techniques and show improved performances in terms of rejection and bandwidth. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 90–93, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10525 [ABSTRACT FROM AUTHOR]

We report first on an experimental analysis of photonic bandgap microstrip-type filters at microwave frequencies. The frequency-selective structure is achieved via ground-plane patterning. The influence of a shielding is addressed in particular. Then, we theoretically analyze the possibility of two-sided patterning for a high dynamic broadband filtering response. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 69–72, 2001. [ABSTRACT FROM AUTHOR]

A way to model and test fiber gratings and fiber grating-based systems in the microwave range is proposed. The method rests on the equivalence relationship found between a fiber grating and a one-dimensional microstrip photonic bandgap structure that consists of a periodic pattern of circles etched in its ground plane. The equivalence assures that the frequency-response of the fiber grating is an upshifted replica of the corresponding frequency to its equivalent microstrip device. Both apodized and nonapodized uniform fiber gratings have been considered and the feasibility of the proposed method has been shown in simulation and measurement. [ABSTRACT FROM AUTHOR]

A bending technique to achieve compactness in the longitudinal dimension of one-dimensional photonic bandgap (PBG) microstrip structures already has been proposed by the authors. The meander PBG reflector had almost the same frequency response as the straight device, but a small ripple appeared due to the periodicity of the meander line employed. Two different techniques to smooth that ripple are proposed and successfully tested. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 211–216, 2000. [ABSTRACT FROM AUTHOR]

Novel wide rejected band devices are obtained using chirping techniques in one-dimensional photonic bandgap microstrip structures with the ground plane etched following a periodic pattern. Full-wave electromagnetic simulations and measurements are provided to compare the frequency responses of structures with a linearly varying period (chirped devices) and those of structures with a constant period (nonchirped or conventional devices), showing the increased bandwidth obtained. ©2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 357–360, 2000. [ABSTRACT FROM AUTHOR]

In this letter, the design of a compact high-power waveguide low-pass filter with low insertion loss, all-higher order mode suppression, and stopband rejection up to the third harmonic, intended for Ka-band satellite applications, is presented. The method is based on step-shaped bandstop elements separated by very short (ideally of zero length) waveguide sections easily manufactured by low-cost computer-controlled milling. Matching is achieved by short input/output networks based on stubs whose heights are optimized following classical approaches. The novel filter presents a reduction in insertion loss and a remarkable increase in the high-power handling capability when compared to the classical waffle-iron filter and alternative solutions previously proposed, while the out-of-band frequency behavior remains unaltered. [ABSTRACT FROM PUBLISHER]

We propose a simple and fast fiber grating model for the analysis and synthesis of 1-D photonic bandgap structures consisting of circles etched in the ground plane of microstrip lines. The relationship between the parameters of the photonic bandgap structure and those for an equivalent fiber Bragg grating having the frequency response of the first shifted to the optical wavelength range is described. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 223–226, 1999. [ABSTRACT FROM AUTHOR]

In this letter, a new method for the design of high-power low-pass harmonic filters in rectangular waveguide technology is proposed. Based on a 2-D arrangement of bandstop elements of sinusoidal profile, a filter with a wide spurious-free frequency response (up to the third harmonic) for the fundamental TE10 mode, as well as higher-order TEn0-mode suppression, is achieved. Compared to the classical waffle-iron solution, the novel proposal has a highly increased power-handling capability for the same frequency specifications. [ABSTRACT FROM PUBLISHER]

A novel microstrip coupled-line directional coupler with enhanced coupling factor is proposed. It is based on the introduction of an electromagnetic bandgap (EBG) structure on the coupled lines to strongly enhance the designed backward coupling. Accurate analytical expressions are obtained for the main design parameters of the coupler. A 3 dB EBG coupler has been designed, simulated and measured, demonstrating 6.4 dB improvement in the coupling level when compared to a classical coupled-line directional coupler. [ABSTRACT FROM AUTHOR]

This letter reports on a new design method for dispersive delay lines in coupled-line technology. Based on the reflective chirped delay line concept, a continuous modulation of the even- and odd-mode characteristic impedances in symmetrical coupled-lines is shown to produce a new structure that presents a flat magnitude response and a linear group-delay variation along the operation frequency band. The use of coupled-lines avoids the need for a circulator giving rise to more practical devices, where the processed signal is redirected to the coupled port instead of being reflected back to the input port, thus providing a valuable effective transmission-type operation. The technique of designing a device is validated for ultra-wideband signal processing applications. [ABSTRACT FROM PUBLISHER]

In this letter, a new technique is proposed for the design of a compact high-power low-pass rectangular waveguide filter with a wide spurious-free frequency behavior. Specifically, the new filter is intended for the suppression of the fundamental TE10 mode over a wide band in much higher power applications than the classical corrugated filter with the same frequency specifications. Moreover, the filter length is dramatically reduced when compared to alternative techniques previously considered. [ABSTRACT FROM PUBLISHER]

We propose and demonstrate a new technique for generating customized pulse-shapes intended for use in ultrawideband (UWB) applications. The technique employs tailored microstrip lines that have been designed using an exact analytical series solution of the synthesis problem derived from the coupled mode theory. This solution permits the synthesis of waveguides and transmission lines with arbitrary impulse responses limited only by the principles of causality, passivity and stability. Time-domain measurements are performed demonstrating the generation of two pulse-shapes using microstrip circuits and satisfying pre-established UWB mask requirements. [ABSTRACT FROM PUBLISHER]

We propose and demonstrate an electronic system achieving continuously tunable time-delays with nanosecond-scale delay excursions for ultra-wideband signals. Our demonstration system yields an adjustable delay of up to 1.6 ns for input signals spanning 3 to 7 GHz. The key component is a dispersive length of microstrip line created by etching a chirped electromagnetic bandgap structure in the conducting strip. [ABSTRACT FROM PUBLISHER]

This letter presents a novel general technique for the design of microwave filters with arbitrary frequency response. It is based on the translation of the microwave specifications to the digital domain, where the well known and readily available digital filter design techniques are applied. By means of these digital techniques, the method provides a straightforward procedure to calculate the poles and zeros corresponding to the analog frequency response that satisfies the target specifications. From the poles and zeros, the microwave filter can be readily obtained using conventional techniques. As an example to demonstrate the proposed technique, a filter with user-defined specifications over two independent passbands has been implemented and successfully tested in microstrip technology. [ABSTRACT FROM PUBLISHER]

In this paper, it is demonstrated that split-ring resonators (SRRs) magnetically coupled to a coplanar waveguide (CPW) structure can be applied to the design of miniaturized band-pass filters. To this end, a two-stage prototype device consisting of a CPW with two signal-to-ground shorts and a series gap, combined with SRRs, is designed and fabricated. By virtue of the subwavelength operation of SRRs at their quasi-static resonance, the filter dimensions can be made to be very small in comparison to conventional distributed implementations. Other relevant features of the proposed structures are: (i) low insertion losses (<3.5 dB) in the allowed band, (ii) out-of-band rejection levels above 30 dB, and (iii) very sharp transition slopes. It is believed that these SRR-based structures can be of interest for the design of planar filters with potential application in future communication transceivers. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 33–35, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20893 [ABSTRACT FROM AUTHOR]

A method to achieve the rejection of multiple spurious passbands in parallel-coupled-line microstrip bandpass filters is proposed. As it was previously demonstrated by the authors, using a continuous perturbation of the width of the coupled-lines following a sinusoidal law, the wave impedance can be modulated so that the first undesired harmonic passband of the filter is rejected, while the desired passband is maintained virtually unaltered. In this letter, the scope of the method is extended to reject multiple spurious passbands by employing different periods in each coupled-line section tuned to the different bands to be rejected. Simulated and measured data show that for an order-seven bandpass filter prototype, a rejection level exceeding 30 dB is obtained in the first four spurious passbands, while the desired pass-band is kept almost unaltered. [ABSTRACT FROM PUBLISHER]

In this letter, spurious passband suppression in microstrip coupled line band pass filters by means of split ring resonators (SRRs) is demonstrated for the first time. By etching SRRs in the upper substrate side, in close proximity to conductor strip, strong magnetic coupling between line and rings arises at the resonant frequency of SRRs. This inhibits signal propagation in the vicinity of that frequency, allowing the rejection of undesired passbands by properly tuning SRRs. To test this novel technique, we have designed and fabricated two different SSRs-based filters. In one case, the rings have been designed to suppress only the first spurious band, and SRRs have been etched at both sides of the 50-Ω access lines. For the other prototype, SRRs have been etched on the active device region (i.e., surrounding the parallel coupled lines) and have been tuned to eliminate the first and second undesired bands. The measured frequency responses for these devices confirm the efficiency of this technique to suppress frequency parasitics, with rejection levels near 40 dBs, leaving the passband unaltered. Since SRRs are small particles (with sub-wavelength dimensions at the resonant frequency), this approach does not add extra area to the final layouts. Moreover, the conventional design methodology of the filters holds. [ABSTRACT FROM PUBLISHER]

It is demonstrated that spurious passband suppression in stepped impedance lowpass filters can be achieved by simply patterning appropriate geometries in the low impedance sections. These patterns consist of concentric rings with splits etched in opposite sides, that behave as sub-wavelength resonators electrically coupled to the line. By tuning ring dimensions, signal propagation is inhibited at the frequencies of interest, and spurious passbands are rejected. The main advantages of the technique are: (i) no additional cascaded stages are needed, (ii) no extra area is added, (iii) the passband is virtually unaltered and (iv) the conventional design methodology of the filter holds. A prototype device fabricated in CPW technology exhibits spurious suppression levels above 30 dBs. [ABSTRACT FROM AUTHOR]

In this letter a super-compact stopband microstrip structure is proposed. The frequency gap is produced by an array of complementary split ring resonators (CSRRs)-a concept proposed here for the first time-etched on the ground plane. This behavior is interpreted as due to the presence of a negative effective dielectric permittivity in the vicinity of resonance. The resulting device produces a deep rejection frequency band with sharp cutoff, and a pass band that exhibits very low losses and good matching. Due to the sub-lambda operation of CSRRs, the electrical size of the device is very small. [ABSTRACT FROM PUBLISHER]

In this paper, coplanar waveguide (CPW) bandpass filters based on capacitively coupled resonators and periodic perturbation in slot width are proposed. Due to periodicity, the structure behaves as a reflector in a certain frequency band and harmonic suppression is achieved. Slot-width modulation has been implemented through the approximation of the ground planes to the conductor strip at periodic locations. The equivalent capacitance of the line is thus enhanced, with the result of a significant slow-wave effect. In comparison to a conventional design, the fabricated prototype is 1.4 times smaller and exhibits significant rejection of frequency parasitics. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 146–148, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11309 [ABSTRACT FROM AUTHOR]

A new type of compact band pass filters based on planar structures with three metal levels is proposed. The central layer consists on a coplanar waveguide (CPW) with periodic wire connections between the central strip and ground planes. In the upper and lower metal levels, split ring resonators (SRRs) are etched and aligned with the slots. The wires make the structure to behave as a microwave plasma, with a negative effective permittivity covering a wide frequency range. SRRs, which are magnetically coupled to the CPW, provide a negative magnetic permeability in a narrow frequency range above their resonant frequency. The result is a band pass structure which supports wave propagation in a frequency interval where negative permittivity and permeability coexist. The bandwidth of the structure can be controlled by tuning the resonant frequency of the upper and lower SRRs and the distance between SRRs. Fabricated prototype devices exhibit very low insertion losses in the pass band (<1.5 dB) and high frequency selectivity. [ABSTRACT FROM PUBLISHER]

A novel coplanar waveguide (CPW) low pass filter based on electromagnetic bandgaps (EBG) with double periodicity has been designed and fabricated. The device consists on a CPW with T-shaped loading capacitances at periodic positions and slot width modulation. By properly choosing the ratio between the two periods of the structure, a huge band gap (more than five times the bandwidth) is obtained through the suppression of spurious frequencies. The fabricated prototypes also exhibit very sharp cutoff, very low insertion loss in the passband and slow wave effect. [ABSTRACT FROM PUBLISHER]

Frequency tuning in stopband filters based on nonlinear transmission lines is demonstrated for the first time. The structure is an electromagnetic bandgap (EBG) coplanar waveguide reflector periodically loaded with varactor diodes, acting as tuning elements. By varying the capacitance of the diodes the phase velocity can be tailored, the result being a wide tuning range for the central frequency of the rejected band. it was also found that the EBG-based reflector is able to inhibit harmonic generation under large-signal driving conditions. [ABSTRACT FROM AUTHOR]

In this work, the coupled mode theory is formulated to analyze distributed periodic structures for microstrip lines. After it, several reasonable approximations are introduced giving rise to analytical solutions for the problem. The obtained results, both numerical and analytical, are checked against measurements showing very good agreement. The proposed method is very attractive for the study of these devices since it avoids the time-consuming full-wave electromagnetic simulations customarily employed and provides analytical solutions that are very useful for analysis and synthesis purposes. [ABSTRACT FROM PUBLISHER]

In this work, coplanar waveguides (CPW) periodically loaded with shunt capacitances and periodically perturbed by varying the distance between the central strip (of constant width) and ground planes are studied. It is demonstrated that the multiple spurious passbands above the Bragg frequency, inherent to the presence of the reactive elements, can be completely and efficiently rejected by means of very simple geometry perturbation. This result is in contrast to previous works, where the rejection of multiple frequencies requires complex layout patterns and reveals that the elimination of spurious frequency bands in periodic loaded CPWs cannot be merely estimated from the Fourier transform of the perturbation geometry. [ABSTRACT FROM PUBLISHER]

In this paper, we report on a design method for chirped delay lines (CDLs) in microstrip technology. They consist in a continuously varying strip width, so that the coupling location between the quasi-TEM microstrip mode and the same but counter-propagating mode is linearly distributed in frequency. High delay×bandwidth products, over frequency ranges of several gigahertzs, can be obtained following this procedure. Experimental data confirm the design method. Real-time Fourier analysis of wideband pulses can be performed using these CDLs [ABSTRACT FROM PUBLISHER]

Photonic bandgap (PBG) structures in microstrip technology have been recently proposed as efficient Bragg reflectors. The periodic patterns employed until now were formed by a distribution of nonconnected holes (cermet topology) etched in the ground plane or drilled in the dielectric substrate, giving rise to single-frequency-tuned band reflectors. In this letter, a novel pattern that follows a continuous profile (network topology) is proposed to simultaneously reject multiple frequency bands. It is formed by the addition of various sinusoidal functions tuned at the design frequencies. Measurements performed for two-and three-frequency-tuned PBG microstrip prototypes show that multiple deep and wide stopbands can be obtained using these novel devices [ABSTRACT FROM PUBLISHER]

A Ku-band high-power lowpass filter with spurious passband suppression up to 40 GHz is proposed in rectangular waveguide technology. The new design consists of a conventional E-plane corrugated lowpass filter cascaded with a quasi-periodic structure tuned to reject the undesired spurious passbands. This new design technique allows the minimum gap of the original corrugated filter to be kept wide enough to permit high-power operation. [ABSTRACT FROM AUTHOR]

A correction to the article "Microstrip coupled-line directional coupler with enhanced coupling based on EBG concept" is presented.

The electromagnetic theory of diffraction and the Babinet principle are applied to the design of artificial metasurfaces and metamaterials. A new particle, the complementary split rings resonator, is proposed for the design of metasurfaces with high frequency selectivity and planar metamaterials with a negative dielectric permittivity. Applications in the fields of frequency selective surfaces and polarizers, as well as in microwave antennas and filter design, can be envisaged. The tunability of all these devices by an applied dc voltage is also achievable if these particles are etched on the appropriate substrate.