Satellite Digital Audio Radio Research Articles

A New L-Shaped Open-Slot Antenna for Diversity Applications of Operated Frequency and Circular Polarization

ABSTRACT This paper presents a novel small differentially-fed open-slot antenna for diversity of the operated frequency and circular polarization. The proposed antenna structure, which consists of an L-shaped open slot and two bent feeding lines, provides two separate effective bandwidths. The proposed antenna achieves the operation bandwidths of a global positioning system (GPS) and satellite digital audio radio (SDAR) service system. To excite the even and odd modes for bandwidth enhancement, a rectangular patch was embedded in the vertical segment of the L-shaped open slot, thereby forming a coplanar-waveguide topology. An additional rectangular patch was placed above the open slot to increase the interport isolation performance between the two feeding ports. After optimization, the measurement results indicated that the final open-slot antenna provided −10-dB reflection coefficient (S11) bands from 1.29 to 1.70 GHz for the GPS operation and from 2.09 to 2.56 GHz for the SDAR application. Measured 3 dB axial-ratio bandwidths of the proposed structure were 410 MHz (28.5%) from 1.23 to 1.64 GHz and 430 MHz (18.4%) from 2.12 to 2.55 GHz for right- and left-hand circular polarization, respectively.

A Compact Cavity-Backed Tri-Band Antenna Design for Flush Mount GNSS (L1/L5) and SDARS Operations

This letter presents a unique compact cavity-backed tri-band antenna design for supporting simultaneous Global Navigation Satellite System (GNSS) ( L 1/ L 5) and Satellite Digital Audio Radio Service (SDARS) operations in a rooftop flush mount configuration. The cavity dimensions are 100 mm in diameter and only 9.35 mm in depth to meet a specific automobile manufacturer's physical dimension requirement. The achieved half-power realized gain bandwidths at L1, L5, and SDARS bands are 85, 54, and 250 MHz, respectively. This design consists of a bottom feeding board, a top GNSS board, and a middle SDARS board. All three boards are connected using vertical wires. The left-hand circular polarization (LHCP) SDARS element is a C-line coupled circular patch element that is excited via a novel traveling-wave proximity-coupling method that maximizes the passage of the out-of-band signals. The right-hand circular polarization (RHCP) dual-ring GNSS element is excited after the SDARS element using two orthogonal tapered-width proximity probes which are connected to two microstrip lines with different lengths for producing 90° phase difference at 1.4 GHz. The entire antenna assembly is connected to a single subminiature version A (SMA) connector. The design specifications and operating principles of the proposed antenna are discussed along with comparisons between the simulation and measurement performance obtained from a fabricated prototype.

A compact circularly polarized isosceles triangular microstrip patch antenna with parasitic elements for multiband application

AbstractIn this research paper, a isosceles triangular radiating patch with two triangular coplanar parasitic elements has been used to design a compact circularly polarized (CP) microstrip patch antenna that can be used for (2.320‐2.345 GHz) satellite digital audio radio systems (SDARS), (2.30‐2.39 GHz) wireless broadband (WiBro), LTE 2300 (2.3‐2.4 GHz), and WIMAX (2.50‐2.69 GHz) application band. Corners of the two parasitic element along with a portion of driver patch has been cut and optimize to obtain CP characteristics of the antenna with broadside radiation pattern. A slot is also introduced and optimized on the radiating patch to improve the impedance matching. Frequency band generated by the antenna is (2.09‐2.64 GHz) having impedance bandwidth of (S11 ≤ −10 dB) 550 MHz 23.25% and two 3‐dB axial ratio (AR) bandwidth of 5.1% (2.29‐2.41GHz) and 1.54% (2.58‐2.62 GHz). The size of proposed antenna is 56 × 52 × 3.2 mm3 in which, FR4 material has been used as dielectric substrate and thin copper plate as radiating patch and ground. Before physical fabrication, HFSS ver13 software has been used to design and analyzed the proposed antenna. It has been found that the measured results of fabricated antenna and simulated results are closely matching.

Interference into radio broadcast satellite uplinks

Radio frequency interference into satellite transmission channels is a matter of concern. There have been many studies of this subject by the ITU (International Telecommunications Union) particularly to mobile user receivers in the satellite radio broadcasting services by IMT (International Mobile Telecommunications) transmitters, since such receivers have high sensitivities (e.g., downlink channel system noise temperatures of under 100 deg. Kelvin) and provide Satellite Digital Audio Radio Service (SDARS) quality using relatively low satellite signal levels on the ground. Recently, proposals have been made by future low orbit satellite constellations, IMT and terrestrial interconnection systems to share radio frequency bands used by the transmission uplinks to radio broadcasting satellites. The broadcasting satellite uplink transmission channel at 7 GHz has typical system noise temperatures of 900 deg. Kelvin followed by very high electronic and antenna amplification. The overall system transmission design is generally set so the satellite broadcast uplink C/N does not appreciably degrade the downlink C/N, since the downlink simultaneously serves than 35 million mobile users with satellite radio service in North America. This paper describes the effect of potential interference into a satellite radio broadcast service from in-band and adjacent band transmissions and from associated intermodulation products by sharing uplink frequency spectrum transmitters. The analysis shows that such sharing services should be carefully arranged in the radio frequencies utilized and limited in flux densities impinging the geostationary orbital arc so harmful interference to radio broadcast satellite services does not occur.

Design and packaging of multi-polarized triple-band antenna for automotive applications

This paper proposes a novel design and packaging of single-fed asymmetric slot loaded triple band antenna with left-hand circular polarization (LHCP) at SDARS, right-hand circular polarization (RHCP) at GPS L5 band, and linear polarization at GSM-1900 that be able to deploy at hand-held device for geo-informatics and surveying applications. Triple-band operation and multi-polarization are obtained by inculcation of asymmetric slots in the patch. The all-inclusive dimensions of the designed antenna is only 51 × 52 × 1.6 mm3, rendering it attractive for the user market. A archetype of the proposed model is fabricated, and its performance is substantiate through measurement. Measured results shows that the antenna exhibits multiple independent polarized radiations, i.e. RHCP and LHCP radiation at two distinct bands namely Global Positioning System (GPS) L5 (1.17645 GHz) and Satellite Digital Audio Radio Service (SDARS) (2.320–2.345 GHz) bands, respectively and linear Polarized radiation at GSM-1900 band. The proposed antenna display good radiation performance when installed on car housing and various other type of housing.

Automotive antenna diversity system for satellite radio with high phase accuracy in low SNR-scenarios

AbstractFor a fast scan-phase satellite radio antenna diversity system a noise correction method is presented for a significant improvement of audio availability at low signal-to-noise ratio (SNR) conditions. An error analysis of the level and phase detection within the diversity system in the presence of noise leads to a correction method based on a priori knowledge of the system's noise floor. This method is described and applied in a hardware example of a satellite digital audio radio services antenna diversity circuit for fast fading conditions. Test drives, which have been performed in real fading scenarios, are described and results are analyzed statistically. Simulations of the scan-phase antenna diversity system show higher signal amplitudes and availabilities. Measurement results of dislocated antennas as well as of a diversity antenna set on a single mounting position are presented. A comparison of a diversity system with noise correction, the same system without noise correction, and a single antenna system with each other is performed. Using this new method in fast multipath fading driving scenarios underneath dense foliage with a low SNR of the antenna signals, a reduction in audio mute time by one order of magnitude compared with single antenna systems is achieved with the diversity system.

A Simple CPW-Fed Monopole Antenna with Reconfigurable CP Frequency and Radiation Pattern

ABSTRACTIn this work, several techniques are presented to switch operated bandwidth and circularly polarized pattern of the coplanar waveguide (CPW)-fed monopole antenna. A fork-like conducted strip monopole is utilized for the radiating element. Two p-i-n (PIN) diodes are embedded in the antenna structure to realize the switchable capability of frequency band and circular polarization. By electronically turning on or off these diodes, a right-hand circularly polarized (RHCP) wave at 1.57 GHz for the global positioning system (GPS) is not only generated, but a left-hand circularly polarized (LHCP) wave at 2.33 GHz for satellite digital audio radio (SDAR) service system is also achieved. Measured results show that the 3-dB axial ratio (AR) bandwidths are 110 MHz (1.49–1.60 GHz, 7.1%) around 1.57 GHz and 70 MHz (2.29–2.36 GHz, 3.0%) around 2.33 GHz, whereas the impedance bandwidths are 430 MHz (1.38–1.81 GHz) and 670 MHz (2.05–2.72 GHz).

Compact satellite antenna module for GPS, Galileo, GLONASS, BeiDou and SDARS in automotive application

A new design concept of a compact satellite antenna module for automotive application is presented, enabling mobile reception of all common Global Navigation Satellite Systems (GNSS), e.g. GPS in L1 and L2 bands, Galileo, GLONASS, BeiDou, as well as reception of Satellite Digital Audio Radio Services (SDARS). The design concept is based on the combination of a dual-band ring structure for GNSS with a single-band ring structure for SDARS which allows easy fabrication in combination with high reception properties. The performance of the antenna module and its fulfilment of the requirements of car manufacturers and service providers is proven by simulated and measured results, showing the high realised gain for circular polarisation, efficiency, matching and decoupling against terrestrial interferers.

A microstrip wideband monopole antenna for multisystem integration by utilizing stepped-impedance structure and L-shaped slot

In this article, a coplanar-waveguide (CPW)-fed dual-band antenna for applications of the multisystem integration has been demonstrated. The resonance analysis of the stepped-impedance (SI) monopole is presented by using the transmission-line analysis method. The frequency-response characteristics of the SI-monopole, such as the resonance condition and harmonic response, are systematically summarized. Furthermore, utilizing several simple techniques, such as bent feeding topology, asymmetric ground plane, and an L-shaped slot etched in the ground plane, a right-hand circularly polarized (RHCP) radiating wave at 1.57 GHz and a left-hand circularly polarized (LHCP) radiating wave at 2.33 GHz are excited for the applications of the global positioning system (GPS) and the satellite digital audio radio (SDAR) service system. After optimization of the geometrical parameters of the proposed antenna, the measured impedance bandwidths of a reflection coefficient less than −10 dB range from 1.40 to 2.98 GHz and from 4.48 to 6.27 GHz, and thus covers most of the commercial wireless communication systems, such as GPS, digital cellular system (DCS), personal communication system (PCS), international mobile telecommunications (IMT)−2000, wireless local area networks (WLAN), and long-term evolution (LTE) 2300/2600. The measured 3-dB axial ratio (AR) bandwidths are about 80 MHz at 1.57 GHz and 100 MHz at 2.33 GHz.

Modified Annular Ring Antenna for GPS and SDARS Automotive Applications

Integrated Global Positioning System (GPS) and Satellite Digital Audio Radio (SDARS) antenna is proposed for automotive use. The GPS antenna is formed by modifying an annular ring antenna operating at TM 12 mode, and the SDARS antenna is placed at the ring center using a slot-loaded degenerate mode TM 11 square patch. The GPS antenna operates at 1575.4 MHz with right-hand circular polarization, and the SDARS antenna operates from 2320 to 2345 MHz with left-hand circular polarization. The antenna is also placed on an automotive model, and simulations with the vehicle are performed. Simulations and measurements of the antenna exhibit good performance for automotive use.

On-glass automotive diversity antenna and LNA design for S-band satellite digital radio

Selection combining diversity system with antennas mounted on windshield and backlite of a vehicle is proposed for satellite digital audio radio applications. Standalone exterior mount antennas on metallic vehicles perform well for satellite digital audio radio applications, but for composite body vehicles or interior mount antennas, antenna performance becomes a real issue. Proposed on-glass two-antenna diversity is one solution for such applications. The antenna correlation is calculated using the S-parameters of the antennas and found to be very low due to many wavelengths separation between the antennas. Design of low noise amplifier, which has sub 1 dB noise figure and good P1dB due to strong cellular signals, is also detailed. A diversity receiver is described and ride tests are performed to assess the performance of the diversity system in real-time, under weak satellite signal environment which is regarded as the most challenging reception condition.

A Wideband Open-Slot Antenna With Dual-Band Circular Polarization

A wideband microstrip-fed open-slot antenna with dual-band circular polarization (CP) has been presented. A bent feeding structure and three slots, including a T-shaped and two inverted-L topologies etched in the ground plane, are designed to excite two orthogonal $E$ vectors with equal amplitude and 90 $^\circ $ phase difference (PD) for a radiating right-hand circularly polarized (RHCP) wave at 1.57 GHz and left-hand circularly polarized (LHCP) wave at 2.33 GHz. The two bands are the operated bandwidth of the global positioning system (GPS) and satellite digital audio radio (SDAR) service system. To improve the impedance bandwidth at the low-frequency band, a parasitic rectangular patch is added on the top plane of the substrate. Several resonances are merged, and thus, a wide impedance bandwidth is obtained. The measured impedance bandwidth of a reflection coefficient $ ranges from 1.45 to 3.93 GHz, and thus covers most of the commercial wireless communication systems, such as GPS, DCS, PCS, IMT-2000, WLAN, LTE, and WiMAX. The axial-ratio bandwidths are 65 MHz at the lower band (1.57 GHz) and 107 MHz at the upper band (2.33 GHz).

State modelling of the land mobile propagation channel for dual-satellite systems

The quality of service of mobile satellite reception can be improved by using multi-satellite diversity (angle diversity). The recently finalised MiLADY project targeted therefore on the evaluation and modelling of the multi-satellite propagation channel for land mobile users with focus on broadcasting applications. The narrowband model combines the parameters from two measurement campaigns: In the U.S. the power levels of the Satellite Digital Audio Radio Services were recorded with a high sample rate to analyse fast and slow fading effects in great detail. In a complementary campaign signals of Global Navigation Satellite Systems (GNSS) were analysed to obtain information about the slow fading correlation for almost any satellite constellation. The new channel model can be used to generate time series for various satellite constellations in different environments. This article focuses on realistic state sequence modelling for angle diversity, confining on two satellites. For this purpose, different state modelling methods providing a joint generation of the states ‘good good’, ‘good bad’, ‘bad good’ and ‘bad bad’ are compared. Measurements and re-simulated data are analysed for various elevation combinations and azimuth separations in terms of the state probabilities, state duration statistics, and correlation coefficients. The finally proposed state model is based on semi-Markov chains assuming a log-normal state duration distribution.

Digital Audio Around the World

DR (or DAB) has been around for several decades but only now is it being adopted and implemented by the commercial broadcast community. There are four types of systems: Eureka 147, DRM, IBOC, and Satellite Digital Audio Radio. There are two types of implementation strategies: use of dedicated spectrum and reuse of existing spectrum for AM and FM broadcasting. Eureka 147 uses dedicated spectrum; DRM and IBOC reuse existing spectrum. In addition, SDAR makes use of terrestrial as well as satellite systems (XM and Sirius). Digital tuner costs vary from US$150.00 to US$1,000.00. Table 3 shows a comparison of each type of system. Although a principal purpose of DR is the enhancement of audio quality, this technology offers additional features such as the ability to integrate and broadcast text, data, and video, weather service information, and satellite maps of your location. In addition, DR technology is adopting the use of software to defined radio capabilities and features that will result in longer equipment life cycles and using common equipment in diverse applications.

Design of a Compact GPS and SDARS Integrated Antenna for Automotive Applications

This letter describes a novel compact solution for integrating a Global Positioning System (GPS) and a Satellite Digital Audio Radio Service (SDARS) antenna in a very small volume to satisfy the requirements of the automotive market. The GPS antenna is a classic small commercial ceramic patch, and the SDARS antenna is designed in order to fit in the reduced space without affecting radiation and band performance of the GPS antenna. The SDARS basic geometry is a square-ring microstrip antenna operating in the frequency range 2.320-2.345 GHz with left-hand circular polarization (LHCP), and it is wrapped around the GPS patch, which receives a right-hand circular polarization (RHCP) signal at 1.575 GHz. The overall volume of the presented integrated antenna solution is only 30 x 30 x 7.6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , rendering it attractive for the automotive market.

Supplemental Declaration of J. Gregory Sidak Concerning the Competitive Consequences of the Proposed Merger of Sirius Satellite Radio, Inc. and XM Satellite Radio, Inc.

Supplemental Declaration of J. Gregory Sidak Concerning the Competitive Consequences of the Proposed Merger of Sirius Satellite Radio, Inc. and XM Satellite Radio, Inc.

Second Supplemental Declaration of J. Gregory Sidak Concerning the Competitive Consequences of the Proposed Merger of Sirius Satellite Radio, Inc. and XM Satellite Radio, Inc. (July 24, 2007)

In this declaration, I critique two reports submitted to the Federal Communications Commission in July 2007 on behalf of XM and Sirius in support of their proposed merger: one by Professor Thomas W. Hazlett and another by Dr. Harold Furchtgott-Roth. I have previously addressed some aspects of both reports in my supplemental declaration, which can be downloaded from the Social Science Research Network.The reports of Professor Hazlett and Dr. Furchtgott-Roth fail to provide evidence that informs the relevant product market definition for this proceeding - namely, whether satellite digital audio radio services (SDARS) customers perceive alternative audio entertainment sources (including MP3 players, Internet radio, and terrestrial radio) as being sufficiently close substitutes such that a hypothetical monopoly provider of SDARS could not profitably increase prices. More importantly, both experts appear to reject the current antitrust paradigm for analyzing mergers. In its place, they offer novel theories for merger review. Even if XM's and Sirius's experts are correct about radically redesigning the framework for antitrust analysis of horizontal mergers, it is not appropriate for the FCC to announce some alternative merger guidelines without a proper rulemaking simply because doing so would suit the current merger proponents.I begin in Part I with a critique of Professor Hazlett's report. Professor Hazlett mischaracterizes which party bears the burden of proof in this merger proceeding, claiming that the burden falls on both merger opponents and regulatory agencies. I demonstrate that by focusing on quality-adjusted prices, Professor Hazlett ignores the merged firm's ability to increase commercials. Professor Hazlett also omits mentioning that SDARS customers would be required to subscribe to a new, more expensive package to receive any increase in quality according to his concept of a quality improvement.Next, I analyze Professor Hazlett's novel tests for product market definition. According to Professor Hazlett, a product market can exist only if the market value of all suppliers of the service exceeds the present value of funds invested. In a later section of his report, Professor Hazlett suggests another novel test for market definition, which considers the relative market value of terrestrial broadcasting properties to satellite radio operators. I demonstrate why these and other novel antitrust theories offered by Professor Hazlett are incorrect and should not be used. Finally, I respond to Professor Hazlett's criticisms of my original declaration.In Part II, I critique Dr. Furchtgott-Roth's report. Dr. Furchtgott-Roth seeks to extend the standard two-year window for entry analysis in merger cases so that nascent services like mobile Internet radio can have time to develop. That approach is not consistent with existing merger law. Dr. Furchtgott-Roth also repeats Professor Robert Willig's argument in the DirecTV-EchoStar proposed merger - that XM and Sirius do not compete against one another, yet each does compete against terrestrial radio and other services. I argue that this interpretation of the extent of existing competition between XM and Sirius is not plausible.Finally, in Part III, I perform an event-study analysis to test XM's and Sirius's hypothesis that the proposed merger would expand output and decrease prices (the procompetitive hypothesis). I examine the abnormal returns of satellite equipment manufacturers around the day on which the proposed merger of XM and Sirius was announced. I find that the market perceived the announcement of the proposed merger between XM and Sirius as bad news for satellite equipment manufacturers, which implies that the proposed merger would result in higher prices for SDARS customers.

Design concept of compact antenna for SDARS applications

A design concept to reduce the overall dimensions of a microstrip antenna using a wrapped radiating structure and embedded slits is proposed. A compact microstrip antenna for SDARS (satellite digital audio radio services) systems is designed and manufactured with light weight and compact size. Comparision between simulations by Ansoft HFSS software and measurement is provided.

Design of small and low-profile antenna for Satellite Digital Audio Radio System

The design and optimisation of a small and low-profile antenna for the Satellite Digital Audio Radio System using a non-dominated sorting genetic algorithm is presented. A fairly omnidirectional elevation gain pattern over −60°<thetas<60° is obtained at the XM frequency band. The height of the antenna is less than 0.19 λ.

S-DARS broadcast from inclined, elliptical orbits

The first Sirius spacecraft was launched on July 1, 2000. Exactly 5 months later, on December 1, the third spacecraft was launched, completing the three satellite S-DARS (Satellite Digital Audio Radio Service) constellation. The three satellites are deployed in inclined, elliptical, geosynchronous orbits, which allow seamless broadcast coverage to mobile users in the contiguous US. Terrestrial broadcast repeaters provide service in urban cores. The system is in operation, providing the first ever S-DARS service. The constellation design results in satellite ground tracks over North America with two satellites always above the equator. High elevation look angles from the mobile ground terminals to the satellites minimize performance degradation due to blockage, foliage attenuation and multi-path. The spacecraft were built by Space Systems/Loral using the 1300 bus modified for operation in high inclination orbits. Each spacecraft was launched using a dedicated Russian Proton booster. The satellite payload is a bent pipe repeater using 7.1 GHz for the uplink and 2.3 GHz for the broadcast transmission. The repeater high-power amplification stage consists of 32 Traveling Wave Tube Amplifiers phase combined to yield a total radio frequency output power of nearly 4 kW at saturated operation. The satellite antennas are mechanically steered to maintain the transmit beam centered on the Contiguous United States and the receive beam centered on the uplink earth station located in Vernon Valley, New Jersey. The satellite payload design and performance are described. The principal spacecraft bus systems are described with emphasis on improvements made for operation in the inclined, elliptical geosynchronous orbits.