A fully-differential base-band transimpedance low-pass filter is designed for use in a direct conversion wireless receiver. Existing base-band transimpedance amplifiers (TIA) often utilize single-pole filters which do not provide good stop-band rejection and may even allow the filter to saturate in the presence of large interferers near the edge of the pass-band. The designed filter is placed in parallel with an existing single-pole TIA filter and diverts stop-band current signals away from the existing filter, providing added rejection and safeguarding the filter from saturating. The presented filter has a bandwidth of 10 MHz, achieves 35 dB rejection at 50 MHz (25 dB in post-layout simulations), and can process interferers as large as 10 mA. The circuit is designed in Jazz 0.18 m CMOS technology, and it is shown, using macromodels, that the design is scalable to smaller, faster technologies.

In this thesis the general Chebyshev filter synthesis procedure to generate transfer and reflection polynomials and coupling matrices were described. Key concepts such as coupled resonators, non-resonant nodes have been included. This is followed by microwave duplexer synthesis. Next, a technique to design dual band filter has been described including ways to achieve desired return loss and rejection levels at specific bands by manipulating the stopbands and transmission zeros. The concept of dual band filter synthesis has been applied on the synthesis of microwave duplexer to propose a method to synthesize dual band duplexers. Finally a numerical procedure using Cauchy method has been described to estimate the filter and duplexer polynomials from measured responses. The concepts in this thesis can be used to make microwave filters and duplexers more compact, efficient and cost effective.

This thesis proposes a novel dual passband filter architecture and develops a design flow and synthesis method for this architecture. The technical contents include the fundamental passband filter design and the further methods for generating the higher second passband and the multiple transmission zeros. This thesis organizes a design flow based on analytical formulation for the proposed dual passband filter architecture. One can follow this design flow to substitute the filter specifications into the formulation and then can obtain the necessary element values for the filter architecture that match the specified specifications. The dual passband filter architecture is finally implemented on LTCC substrate for WLAN (IEEE 802.11 a/b/g) applications with verification of S parameters using EM-simulation and actual measurement.

abstract: With the desire of high standards of comfort, huge amount of energy is being consumed to maintain the indoor environment. In US building consumes 40% of the total primary energy while residential buildings consume about 21%. A large proportion of this consumption is due to cooling of buildings. Deteriorating environmental conditions due to excessive energy use suggest that we should look at passive designs and renewable energy opportunities to supply the required comfort. Phoenix gets about 300 days of clear sky every year. It also witnesses large temperature variations from night and day. The humidity ratio almost always stays below the 50% mark. With more than six months having outside temperatures more than 75 oF, night sky radiative cooling promise to be an attractive means to cool the buildings during summer. This technique can be useful for small commercial facilities or residential buildings. The roof ponds can be made more effective by covering them with Band Filters. These band filters block the solar heat gain and allow the water to cool down to lower temperatures. It also reduces the convection heat gain. This helps rood ponds maintain lower temperatures and provide more cooling then an exposed pond. 50 μm Polyethylene band filter is used in this study. Using this band filter, roof ponds can be made up to 10% more effective. About 45% of the energy required to cool a typical residential building in summer can be saved. / Dissertation/Thesis / M.S. Architecture 2013

Yes / A Novel design of a curved single-layered frequency selective surface with an 11 × 11 array of a 13 × 13 mm-sized unit cell has been merged with a miniaturized, CPW-fed ultra-wideband monopole of dimensions (20 × 25 mm2) for gain enhancement. The suggested prototype, crafted on an FR-4 dielectric substrate and demonstrates a very broad bandwidth starting from 2.66 to 17.98 GHz (148%), which covers the entire UWB frequency band. The combined antenna-curved FSS reflector shows a very important gain improvement from 0.2–5.4 dB to 8.8–14.9 dB, having a peak gain increase of 10 dB at 10.6 GHz. Basic design features were studied and discussed through simulations, yielding promising results The proposed structure can be used in UWB and GPR applications. / The full-text of this article will be released for public view at the end of the publisher embargo on 31 Oct 2024.

Approved for public release, distribution is unlimited / In this study, the use of multi narrow-band filters was explored to correlate or fuse information to improve detection and recognition for specific targets of interest. To fully understand the viability and limitations of narrow band filters in thermal imaging, laboratory test procedures were first designed to characterize thermal images using common performance parameters, particularly the Noise Equivalent Temperature Difference (NETD), the Modulation Transfer Function (MTF) and the Minimum Resolvable Temperature (MRT). An available thermal imager, the Cincinnati Electronics IRRIS-256LN, and a newly purchased thermal imager, the Indigo Systems Merlin InSb Laboratory Camera, were investigated and compared. The MRT measurement showed a superior cut-off spatial frequency of 1.33 cycle/mrad for the Merlin camera, compared with 1.18 cycle/mrad for the Cincinnati, with similar sensitivity of about 0.1 ʻC for both cameras. Below cut-off the Modulation Transfer for the Merlin was approximately twice that of the Cincinnati. NETD measurements for both systems were inhibited by excess noise in the measurement system. The Merlin camera was consequently employed for further research on narrow band images. Three commercially available narrow band filters, 4110/4720 nm, 4540/4720 nm and 3750/4020 nm, were selected to isolate the "red" and "blue" spike signatures of plume emission and aerodynamic heating found in the signature of fast moving air targets. Similar sensor characterization was carried out with these filters, however, quantitative performance parameter measurements were hindered by excessive measurement system noise. As a preliminary study in multi-spectral image analysis, spectral features of hydrocarbon combustion were extracted from correlated narrow-band images of a laboratory propane flame. Digital analysis using software statistical tools showed potential for discrimination of hydrocarbon emission from other thermal sources by correlating pixel number and pixel radiant intensity. / Captain, Singapore Armed Forces

No / A novel multi-standard dual-wide band filter with a compact size of only 8.8 mm by 16.8mm is designed and developed for transceiver devices. The proposed filter has a fundamental bandwidth of 1.6GHz with fractional bandwidth (FBW) of 29.7% centered at the 5.4GHz band, and second bandwidth of 300.0MHz with FBW of 3.6% centered at the 8.15GHz band. The basic dual-wide bandwidth is attributed to the interaction of the novel modified polygon pair and upper stub loaded stepped impedance resonator. Moreover, the added down stub loaded stepped impedance resonator (SLSIR) further enhances the pass band performance by widening the bandwidth and optimizing reflection coefficient performance considerably. To validate the proposed ideas, the multi-standard filter is designed and simulated by Ansoft HFSS software. The simulated results agree well with the theory predictions. The featured broad bandwidths over two frequency bands and the miniaturized size of the proposed filter make it very promising for applications in future multi-standard wireless communication.

The diploma thesis is focused on design and optimalization of digital octave and fraction-octave band filters. This thesis describe the behavior of filters in systems with fixed point arithmetics and investigate the impact of quantization coefficients for frequency response of filter. Filters, whitch has been designed, are implemented into simple software in C. Designed filters are in accordance with standard IEC 61260.

In recent years, the wireless industry has witnessed tremendous development for the defense and commercial segments. The explosive growth in the modern radio frequency and microwave systems leads to an increased interest in the research of miniaturized microwave circuits with superior performance. Broadband components, in particular band pass filters (BPFs) and couplers are some of the widely used components in the modern communication systems, software defined radios, cognitive radios, imaging systems and positioning radars. In order to meet these requirements, the use of innovative geometries, a thorough understanding of their behavior by appropriate analytical techniques and the use of appropriate fabrication approaches are essential. This thesis is an effort in this direction. In this thesis work, an aperture in the ground plane is used to achieve the tight coupling in the edge and broadside-coupled coupled lines which may be otherwise difficult due to the fabrication limitations. Since microstrip lines with an aperture in the ground plane are found to be very useful in various MIC and MMIC components, closed form analytical expressions developed here will be useful for their initial synthesis. The performances of components using these are enhanced using open/short circuited resonators, spurlines and stubs. A quasi-static approach has been investigated to obtain simple closed form expressions for a microstrip line with a rectangular aperture in the ground plane. The effect of a rectangular aperture in the ground plane has been incorporated in the commonly used expressions of a regular microstrip line by introducing the concept of an equivalent effective height. The expressions for the effective height microstrip geometries with defected ground are obtained and this has been further extended to various possibilities of two-conductor and three-conductor coupled lines. Analysis of the filters and the couplers are mainly based on the even and odd mode propagation characteristics of coupled lines. This approach is extended in this thesis for three conductor coupled lines. Novel broadband BPFs and couplers and dual band pass filters employing various coupled line configurations and defected ground have been developed in this research work. Most of these components have been implemented on a regular microwave laminate or LTCC medium (planar or multi-layer) and tested for the required RF performances. The experimental results were compared against the analytically computed results based on the circuit models and the full wave simulations using electromagnetic (EM) simulations for the validation. The results are in good agreement. With practical requirements of the organization in mind, additional design elements such as open circuit stubs have been incorporated in some of these designs to achieve the desired performance. It is expected that the wideband filter (3.0GHz to 3.8GHz) and the broadband coupler (4GHz to 6GHz) developed in this thesis work would be deployed in systems developed at the Central Research Laboratory, Bharat Electronics Limited, Bangalore, India. In summary, the present doctoral work strives to (i) establish a simplified analysis method for the microstrip lines and coupled microstrip lines with a rectangular aperture in the ground plane, (ii) extend the even and odd mode analysis of the coupled lines for several new coupled line configurations, (iii) design novel broadband microwave filters, dual band filter and couplers using both these, (iv) fabricate these devices using the planar technologies including LTCC, and (v) validate the analysis and design with important practical applications.