A lumped component programmable delay element for Ultra-Wideband beamforming
11 Nov 2013-pp 1-4
TL;DR: A ladder filter based programmable time delay element for beamforming in Ultra-Wideband (UWB) systems is introduced and achieves lower power dissipation, better area efficiency, and finer delay and gain resolution more efficiently.
Abstract: We introduce a ladder filter based programmable time delay element for beamforming in Ultra-Wideband (UWB) systems When compared to conventional methods based on the tapped delay line architecture, our technique achieves lower power dissipation, better area efficiency, and finer delay and gain resolution more efficiently The proposed architecture is more scalable, has better parasitic absorption capability and highly programmable with delay and gain resolution dependent only on transconductor resolution A prototype delay line designed for the 31-106 GHz UWB range achieves a delay range of 80 ps with 05 ps resolution and a gain range of -30 dB to +10 dB with 015 dB step Fabricated in a 025 μm SiGe BiCMOS process, the delay element occupies an active area of 1 mm2 and consumes 47 mW from a 25 V supply A four antenna beamforming system using the delay element can achieve scanning range of ± 51° with resolution of 086 ° for antenna spacing of 10 mm
Citations
More filters
TL;DR: A ladder filter-based programmable time-delay element for beamforming in ultra-wideband (UWB) systems and a lumped-element realization becomes possible by approximating e-std as a ratio of polynomials (based on Taylor and Padé expansions).
Abstract: We introduce a ladder filter-based programmable time-delay element for beamforming in ultra-wideband (UWB) systems. Such a lumped-element realization becomes possible by approximating e
-std
as a ratio of polynomials (based on Taylor and Pade expansions). When compared with conventional methods based on the tapped delay-line architecture, the proposed technique achieves lower power dissipation, higher delay range and resolution, and better area efficiency. A prototype delay line designed for the 3.1-10.6 GHz UWB range achieves a delay range of 140 ps and a gain range of -30 dB to +10 dB. Fabricated in a 0.25 μm SiGe BiCMOS process, the delay element occupies an active area of 1 mm
2
and consumes 53 mW from a 2.5 V supply. A four-antenna beamforming system using the delay element can achieve a scanning range of ±61
°
with 0.86 °
resolution for an antenna spacing of 15 mm.
23 citations
Cites methods or result from "A lumped component programmable del..."
...Thanks to an improved PCB layout for the monopulse generator (thereby reducing reflections), better time-domain responses were obtained compared with those in [20]....
[...]
...One possible approximation using the Taylor series and its implementation aspects were briefly described in [20]....
[...]
TL;DR: In this paper, a uniform linear array (ULA) digital beamformer with enhanced selectivity over conventional true-time delay-sum (TTDS) beamforming is proposed for scanned aperture applications.
Abstract: A uniform linear array (ULA) digital beamformer with enhanced selectivity (interference rejection) over conventional true-time delay-sum (TTDS) beamforming is proposed for scanned aperture applications. Conventional TTDS transfer function, which contains only zero-manifolds, is modified by introducing complex pole-manifolds based on 2-D infinite impulse response (IIR) digital beam filters, thereby achieving enhanced selectivity for the same number of antennas in the ULA. For a ULA of 64 antennas, desired direction of arrival (DOA) 30° and interference DOA -60° from array broadside, a relative improvement in signal-to-interference ratio (SIR) of 7 dB is verified. For 128-element ULA, interference DOA -10°, a relative improvement in SIR of 5-10 dB is obtained for the desired DOA in the range 10°-90°. The projected improvements are independent of the weights of the conventional phased-array, TTDS, or filter-sum beamformer used because the method does not change the zero-manifolds of the original array pattern.
8 citations
TL;DR: In this article, a wideband true time delay is proposed based on 0.25- $\mu \text{m}$ GaAs pHEMT technology, where the trombone topology is adopted for achieving low variation in insertion loss of different delay states.
Abstract: A wideband true time delay is proposed based on 0.25- $\mu \text{m}$ GaAs pHEMT technology. The novel trombone topology is adopted for achieving low variation in insertion loss of different delay states. The fourth-order and second-order inductive all-pass networks (APNs) are operating as delay cells between input and output lines. By selecting different transmission ways, 3 bit with the step of 14 ps and maximum delay range of 98 ps are realized. Measurement results show the insertion loss of 3.8–10.5 dB over the frequency bandwidth of 6–16 GHz. The variation in insertion loss is less than ±1.4 dB. The chip area with pads is 1.955 mm2 and the power consumption is 110 mW.
6 citations
31 Oct 2015
TL;DR: UWB indoor channels extracted from practical measurements are combined with circular horn antenna to characterize the channel properties and to evaluate the system performance, reminding us that when antenna beamforming is used to obtain array gain, the beamwidth should be carefully designed to obtain optimal performance, especially in the NLOS environments.
Abstract: Recently UWB beamforming attracts significant research attention to obtain spatial gain in the form of antenna array. It is commonly believed that directional antenna based communication could improve the system performance. In order to further make clear the relationship between system performance and the antenna radiation pattern, UWB indoor channels extracted from practical measurements are combined with circular horn antenna to characterize the channel properties and to evaluate the system performance. The direction related channel parameters like angle of departure (AOD) and angle of arrival (AOA) are obtained by SAGE algorithm from the measurement results. Using directional antenna with a certain half power beamwidth (HPBW), the channel delay will decrease because the multipath components the receiver could collect are reduced. In the line of sight (LOS) environments, the channel capacity increases with the beamwidth decreasing and is always larger than that of an omnidirectional antenna. Similarly, the bit-error-rate (BER) performance of RAKE receiver is improved with the beamwidth becoming smaller. However in the non-line of sight (NLOS) environments, the conclusions are not so simple. The capacity and BER performance are not always better with directional antennas. And the variation trend between the system performance and the antenna beamwidth disappears. This is mainly because that there exist no dominant strong path components like in the LOS environments. This reminds us that when antenna beamforming is used to obtain array gain, the beamwidth should be carefully designed to obtain optimal performance, especially in the NLOS environments.
1 citations
Cites background from "A lumped component programmable del..."
...One research aspect is the design of delay element [15-16]....
[...]
01 Dec 2014
TL;DR: UWB indoor channels extracted from practical measurements with omnidirectional antenna are combined with circular horn antenna to evaluate the channel capacity in the line of sight (LOS) environments and in the non-line of Sight (NLOS) environments.
Abstract: Recently UWB beamforming attracts significant research attention to obtain spatial gain in the form of antenna array. It is commonly believed that directional antenna based communication could improve the system performance. In order to further make clear the relationship between system performance and the antenna radiation pattern, UWB indoor channels extracted from practical measurements with omnidirectional antenna are combined with circular horn antenna to evaluate the channel capacity. In the line of sight (LOS) environments, the channel capacity increases with the antenna beamwidth decreasing and is always larger than that of omnidirectional antenna. However in the non-line of sight (NLOS) environments, the capacity is not always better with directional antenna. And the change consistency between the capacity and the antenna beamwidth disappears. This reminds us that when antenna beamforming is used to obtain array gain, the beamwidth should be carefully designed to obtain optimal performance, especially in the NLOS environments.
Cites background from "A lumped component programmable del..."
...For recent beamforming systems [3], [4], it’s necessary to further make clear the relationship between antenna pattern and the system performances....
[...]
References
More filters
27 Nov 2007
TL;DR: A fully integrated CMOS ultra-wideband 4-channel timed array receiver for high-resolution imaging application and a path-sharing true time delay architecture to reduce the chip area for integrated circuits are presented.
Abstract: A fully integrated CMOS ultra-wideband 4-channel timed array receiver for high-resolution imaging application is presented. A path-sharing true time delay architecture is implemented to reduce the chip area for integrated circuits. The true time delay resolution is 15 ps and the maximum delay is 225 ps. The receiver provides 11 scan angles with almost 9 degrees of spatial resolution for an antenna spacing of 3 cm. The design bandwidth is from 1 to 15 GHz corresponding to less than 1 cm depth resolution in free space. The chip is implemented in 0.13 mum CMOS with eight metal layers, and the chip size is 3.1 mm by 3.2 mm. Measurement results for the standalone CMOS chip as well as the integrated planar antenna array and the CMOS chip are reported.
126 citations
"A lumped component programmable del..." refers background in this paper
...The transfer function from vin to v1 in Ladder-1 can be shown to be of the all-pole low pass kind and is denoted by 1/D(s)....
[...]
TL;DR: In this article, a fully integrated UWB beam-former with controllable true time delay and power gain is reported, achieving a 4-bit delay variation for a total of 64 ps of achievable group delay with 4-ps resolution, a 5-dB gain variation in 1-dB steps, and a worst case -3dB gain bandwidth of 13 GHz.
Abstract: Ultra-wideband (UWB) beam-forming, a special class of multiple-antenna systems, allows for high azimuth and depth resolutions in ranging and imaging applications. This paper reports a fully integrated UWB beam-former featuring controllable true time delay and power gain. Several system and circuit level parameters and characterization methods influencing the design and testing of UWB beam-formers are discussed. A UWB beam-former prototype for imaging applications has been fabricated with the potential to yield 20 mm of range resolution and a 7deg angular resolution from a four-element array with 10 mm element spacing. The UWB beam-former accomplishes a 4-bit delay variation for a total of 64 ps of achievable group delay with a 4-ps resolution, a 5-dB gain variation in 1-dB steps, and a worst case -3-dB gain bandwidth of 13 GHz. Overall operation is achieved by the integration of a 3-bit tapped delay trombone-type structure with a 4-ps variable delay resolution, a 1-bit, 32-ps fixed delay coplanar-type structure, and a variable-gain distributed amplifier. The prototype chip fabricated in a 0.18 mum BiCMOS SiGe process occupies 1.6 mm2 of silicon area and consumes 87.5 mW from a 2.5-V supply at the maximum gain setting of 10 dB
95 citations
TL;DR: This paper presents an efficient technique to generate a scalable double-pi circuit model for spiral inductors using a relatively simple single-pi model and converts the model to the double- pi model according to the physics-based conversion algorithm.
Abstract: This paper presents an efficient technique to generate a scalable double-pi circuit model for spiral inductors. The double-pi equivalent circuit is widely used to build an inductor library because of its high accuracy over a wide frequency range. However, direct parameter extraction for the double-pi model and scalable fitting for each parameter are complicated due to the large number of circuit elements. The proposed method performs a scalable modeling using a relatively simple single-pi model and converts the model to the double-pi model according to the physics-based conversion algorithm. For this purpose, physical relations between the single-pi and double-pi equivalent circuits for a spiral inductor have been derived. The proposed technique is verified by developing a scalable inductor library using 0.13-mum CMOS technology.
41 citations
"A lumped component programmable del..." refers background in this paper
...The authors also thank Dr.H.Krishnaswamy of Columbia University for useful comments on the manuscript....
[...]
TL;DR: The proposed technique, which is term the lumped parameter equalizer, addresses several of the problems associated with conventional microwave equalizers based on the tapped delay line structure and is suitable for combating inter-symbol-interference at very high data rates.
Abstract: We present a low power analog adaptive equalization technique suitable for combating inter-symbol-interference at very high data rates. The proposed technique, which we term the lumped parameter equalizer, addresses several of the problems associated with conventional microwave equalizers based on the tapped delay line structure. The theory is given, and simulation results comparing it with the performance of ideal tapped delay line filters are shown. Circuit implementations are discussed, along with the effect of nonidealities on equalizer performance.
9 citations
"A lumped component programmable del..." refers methods in this paper
...The efficacy of these techniques were demonstrated by measurements from a test chip....
[...]