Compact Ultra-wideband Microstrip Research Articles

A Novel Compact Ultra-Wideband Dual-Notch Microstrip Antenna

This article presents the results of a novel and compact ultra-wideband dual-notch microstrip antenna excited using a coplanar waveguide feed. The antenna is comprised of two circular radiation patches with a rectangular slot to enhance its impedance bandwidth and two open-circuit stubs that generate high attenuation notches at the desired frequencies. The notch frequency can be controlled by changing the length of the stubs. The proposed antenna exhibits an impedance bandwidth of 123% from 2.45 to 10.3 GHz, significantly satisfying the Federal Communication Commission's ultra-wideband frequency range, while showing the band rejection performance in the frequency bands of 3.3 to 3.8 GHz and 5 to 5.9 GHz. The antenna was fabricated on a standard dielectric substrate, and its measured results are used to verify the simulated performance. The empirical results indicate that the proposed antenna is well suited to be integrated within various portable devices for ultra-wideband operation.

Compact UWB Bandpass Filter With a Notched Band Using Radial Stub Loaded Resonator

In this letter, a novel compact ultra-wideband (UWB) microstrip bandpass filter (BPF) with a notched band is presented by using the proposed radial stub loaded resonator (RSLR). The RSLR, on the one hand, is able to control two tunable transmission zeros separately and on the other hand, has the ability to provide a notched band. In addition, the vertical dimension of the UWB BPF can be significantly reduced by using RSLR, as compared with the UWB BPF based on the conventional stub-loaded resonator (SISLR). For validation, two UWB BPFs, one without the notched band and the other with a notched band at 8.0 GHz for rejecting satellite-communication signal, are developed and fabricated. Measured results show two fabricated filters have the merits of low insertion losses, sharp rejections and flat group delays. Moreover, two filters exhibit the simple topologies and compact sizes.

A fast design approach of compact microstrip multiband bandpass filters

AbstractA simplified technique is used to design multiband bandpass filters using a compact ultrawideband (UWB) microstrip bandpass filter with spiral‐shaped λg/2 resonators, spaced apart by λg/4.Pairs of transmission zeros are generated on predefined locations in the UWB to create dual‐, triple‐, or quad‐band bandpass filters, as desired. The bandwidth and location of the sub‐bands can be easily controlled by the locations of the transmission zeros. These are generated by inserting additional resonators with predicted lengths. Highly selective quasielliptic multiband controllable responses can be achieved. Equations for fast calculations of filter dimensions are derived. Measurements show excellent agreement with the simulations. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1075–1079, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26742

Compact Wideband Microstrip Bandpass Filter Using Quasi-Spiral Loaded Multiple-Mode Resonator

In this letter, a new model for further reducing the size and increasing the bandwidth (BW) of a class of bandpass filter (BPF) utilizing multi-mode resonator is presented. A new technique based on spiral transmission line loading to achieve higher BW and further size reduction is analyzed for this class of BPF. A compact ultra wideband microstrip BPF is proposed by using this technique. The capability of tuning the transmission zeroes in the proposed model is also studied. Estimates for the frequencies of these transmission zeroes are directly presented. The overall BW of the proposed BPF is shown to be increased more than 12.6% and its size to be reduced more than 70% compared with the conventional ones. The proposed BPF provides a relatively wide 3 dB fractional bandwidth of 72.6% frequency response with two transmission zeros at the lower and upper stop-bands to provide a very sharp cutoff and low passband insertion-loss and good return-loss characteristics.

A modified design approach for compact ultra-wideband microstrip filters

A modified design approach for compact ultra-wideband microstrip filters

Compact Ultra-Wideband Bandpass Filter Using Dual-Line Coupling Structure

This letter presents a novel compact ultra-wideband (UWB) microstrip bandpass filter with spurious response suppression. A dual-mode ring resonator is constituted to allocate its first two resonant frequencies in the UWB band, and the dual-line parallel-coupled structure is used in this compact UWB filter, which is expected to achieve much tighter coupling degree. Simulated and measured results are found in good agreement with each other, showing a wide passband from 4.9 to 10.9 GHz, 15 dB return loss bandwidth of about 5 GHz, minimum insertion loss of 0.49 dB at 7.3 GHz, and wide upper stopband with more than 20 dB attenuation up to 20 GHz.

Ultra-wideband electronically tunable pulse generators

We report on the development of new low-cost, compact ultra-wideband microstrip pulse generators capable of varying the pulse duration electronically. These electronically tunable pulse generators generate an initial step function using a step recovery diode, which is then converted into pulses of various durations by alternately switching on one of the switches, realized by PIN diode or MESFET, spatially located along a short-circuited transmission line. Representative pulse-duration variations from 300 to 800 ps have been demonstrated experimentally and theoretically. Good symmetry and low distortion have been achieved for the pulses. Measured results also confirm the simulations.