Showing papers on "Folded inverted conformal antenna published in 1994"
TL;DR: In this paper, the authors present a microstrip antenna with a dielectric substrate and a height varying between lambda /20 and lambda /100, at which the "folded dipole" adaptation techniques are not applicable.
Abstract: In reply to the Comment (given by Burbery, R.A., Elect., Lett., vol., p. 745, 1994) we wish to say: (i) Our antenna is a microstrip antenna with a dielectric substrate and a height varying between lambda /20 and lambda /100. At such heights the 'folded dipole' adaptation techniques are not applicable. >
246 citations
20 Jun 1994
TL;DR: The effect of the shorting posts on the performance of the microstrip antenna is studied experimentally and depends on different parameters like the number of the posts, the radius of each post and the thickness of theMicrostrip antenna which determines the length of the Posts.
Abstract: In many antenna applications, the size of the antenna is considered as an important factor in the design process. Therefore, short circuit microstrip antennas are widely used because the short circuit antenna can realize the same resonant frequency, at about half the size of the standard microstrip antenna. The shorted microstrip antenna is constructed by short-circuiting the zero potential plane of an ordinary microstrip antenna excited with a dominant mode. Physically, this short circuit may be complete, by wrapping a copper strip around the edge of the antenna, or it may be simulated by shorting posts. From the manufacturing point of view, construction of shorting posts is much easier than wrapping a copper strip around the edge of the antenna. In the present paper, the effect of such shorting posts on the performance of the microstrip antenna is studied experimentally. However, the effect of the shorting posts depends on different parameters like the number of the posts, the radius of each post and the thickness of the microstrip antenna which determines the length of the posts. The effect of each of these parameters is investigated and presented. >
125 citations
TL;DR: The monopole wire patch antenna as discussed by the authors is a member of a well known family of monopole variants, well known and much used in the aircraft antenna industry, and was developed by Seeley in the late 1950s.
Abstract: The monopole wire patch antenna is described as a new invention. It is, in fact, a member of a well known family of monopole variants, well known and much used in the aircraft antenna industry. Some of the early development work was done by Seeley in the late 1950s. The antenna had also been developed by Willoughby and was the subject of UK patents.
47 citations
TL;DR: In this paper, the resonant frequency of a coaxial-probe-fed rectangular microstrip antenna tuned by a number of passive metallic posts suitably placed within the antenna's boundary is obtained by using the frequency expression in the absence of the post.
Abstract: The resonant frequency of a coaxial-probe-fed rectangular microstrip antenna tuned by a number of passive metallic posts suitably placed within the antenna's boundary is obtained by using the resonant frequency expression in the absence of the post. The resonant frequency in the absence of the post is calculated from the fringing field extension and effective relative permittivity expressions. The theoretical resonant frequency results of tunable rectangular patch antenna obtained by using this method are in good agreement with experimental results available in the literature. © 1994 John Wiley & Sons, Inc.
45 citations
TL;DR: Co- and cross-polar radiation patterns in E- and H-plane prove that the antennas also have favorable radiation characteristics in a wide bandwidth (at least 18%) and are presented that allows the straightforward and optimal design of transmitting and receiving antennas with multiple active stages.
Abstract: This paper deals with the design of broadband active microstrip antennas where the amplifier is integrated with the radiator. Theoretically sound definitions for gain and noise figure of the active antenna are introduced, and their relationships with the definitions for the composing circuit and radiator parts are explained. A sequential design procedure is presented that allows the straightforward and optimal design of transmitting and receiving antennas with multiple active stages, taking into account input and output matching, the gain-versus-frequency curve as well as the noise performance. The theoretical concepts are illustrated with two examples: one of a transmitting active antenna and one of a receiving antenna. The former one is a two-stage design that achieves nearly 25% of bandwidth with regard to gain and matching and 24 dB gain improvement as compared to the matched passive antenna. The second one is a receiving antenna (one stage) with a measured noise figure of 1.2 dB in a bandwidth of over 17% and a gain improvement of 11.9 dB over the corresponding passive antenna. Finally co- and cross-polar radiation patterns in E- and H-plane prove that the antennas also have favorable radiation characteristics in a wide bandwidth (at least 18%). >
44 citations
TL;DR: In this paper, a simple expression for the effective relative dielectric constant of an electrically-thick circular microstrip antenna with an air gap is presented. But this expression is not applicable to the case of a single antenna with air gap.
Abstract: A very simple expression for the effective relative dielectric constant is presented for an electrically-thick circular microstrip antenna. The theoretical resonant frequency results obtained by using this new expression are in good agreement with the experimental results available in the literature. The expression proposed can also be used in the calculation of the resonant frequency of a circular microstrip antenna with an air gap.
32 citations
TL;DR: The resonant frequencies of equilateral triangular microstrip antenna calculated by Gang are compared with the experimental results of Dahele and Lee (1987) and a new closed-form expression is suggested.
Abstract: The resonant frequencies of equilateral triangular microstrip antenna calculated by Gang (see ibid. vol.37, no.2, p.245, 1989) are compared with the experimental results of Dahele and Lee (1987). When computing the resonant frequencies of equilateral triangular microstrip antenna, using the same equations proposed by Gang, we obtained different results, which are given, from Gang's results. For an equilateral triangular microstrip antenna, the resonant frequencies obtained from the cavity model with perfect magnetic walls are given by the formula shown. In this work, we suggest a new closed-form expression. We compared our computed values of the resonant frequencies for the first five modes of the equilateral triangular patch antenna with theoretical and experimental results reported by other scientists. >
21 citations
Patent•
19 Apr 1994
TL;DR: In this paper, a small microstrip antenna (200) is proposed for portable electronic devices including pagers, telephones, and portable computers, which can fit within a standard PCMCIA slot in portable computers.
Abstract: A small microstrip antenna (200) useful in portable electronic devices including pagers, telephones, and portable computers. The microstrip antenna (200) includes a ground plane layer (212), a dielectric layer (214), and a radiating patch (216) with a rectangular ring (250) formed therein. The radiating patch (216) is short circuited to the ground plane layer (212) along a shorted edge (222). The ring (250) may be positioned offset so that it is closer to the short circuited edge (222) than to the radiating edge (220). The antenna can fit within a standard PCMCIA slot in portable computers. The small size of the antenna allows orientation within a housing to optimize the radiation from the antenna. The antenna is useful in stand alone computers.
13 citations
23 May 1994
TL;DR: In this paper, the FDTD algorithm is used to simulate a two element active antenna which is capable of three different coupled oscillation modes, and the analysis correctly predicts which modes will be stable in the steady state under different loading conditions.
Abstract: The FDTD algorithm is used to simulate a two element active antenna which is capable of three different coupled oscillation modes. This analysis correctly predicts which modes will be stable in the steady state under different loading conditions. The predicted oscillation modes, oscillation frequencies and radiation patterns are compared with experimental data. >
13 citations
TL;DR: In this article, a simple curve-fitting expression for the bandwidth of resonant rectangular microstrip antennas is presented, derived from numerical results available in the literature, and is useful for many engineering purposes.
Abstract: A new very simple curve-fitting expression is presented for the bandwidth of resonant rectangular microstrip antennas. It is derived from numerical results available in the literature, and is useful for many engineering purposes. The results obtained by using this expression are in conformity with those reported elsewhere. © 1994 John Wiley & Sons, Inc.
12 citations
TL;DR: A simple technique to improve the impedance bandwidth of a circular microstrip patch antenna using two sectoral slots is proposed, and more than 5% impedance bandwidth is obtained.
Abstract: A simple technique to improve the impedance bandwidth of a circular microstrip patch antenna using two sectoral slots is proposed. Using this design more than 5% impedance bandwidth is obtained. The added advantage of this new antenna is that it can be fed by a 50-ω microstrip line. © 1994 John Wiley & Sons, Inc.
01 Oct 1994
TL;DR: In this paper, an active receiving microstrip antenna operating around 10 GHz with a GaAs MESFET as active part of the antenna is presented, where simulated and measured results of noise figure and power gain along with the corresponding bandwidth are given in addition to customary antenna parameters.
Abstract: An active receiving microstrip antenna operating around 10 GHz with au GaAs MESFET as active part of the antenna is presented. With the design proposed here, low-noise active receiving antennas with considerably improved bandwidth can be realized. Simulated and measured results of noise figure and power gain along with the corresponding bandwidth are given in addition to customary antenna parameters. Possibilities for noise figure measurement with this non-insertable device have been investigated and an alternative to known procedures is presented.
TL;DR: In this paper, an active microstrip patch antenna with a GaAs MESFET on the patch periphery and the circuit acting as a self-oscillating radiating element is presented.
Abstract: This article discusses the application of a synthesis method for, and the subsequent experimental characterization, of an active microstrip patch antenna. The active antenna incorporates a GaAs MESFET on the patch periphery and the circuit acts as a self-oscillating radiating element. The MESFET and the antenna are mounted on the same side of the circuit, thereby preserving the conformal nature of the structure. The synthesis approach described is based on the method of harmonic balance and allows optimal FET terminations to be selected for a predefined, added power at a specified frequency of operation. Application of a time domain simulator is illustrated in order to demonstrate start-up performance and limit cycle formation in the presence and absence of a frequency entrainment signal. The issue of stability of the active element is also addressed using a modified device/load line method. Theoretical and experimental results are presented for the external quality factor, locking power/phase variation, and power and frequency pushing characteristics of the active antenna. Finally, the effect on oscillator behavior of the mutual coupling between the microstrip patch and the active antenna distributed embedding elements is discussed.
TL;DR: In this paper, a cylindrical dielectric resonator is placed on top of a circular microstrip antenna and the resonant frequency and the input impedance of the antenna are altered.
Abstract: A cylindrical dielectric resonator is placed on top of a circular microstrip antenna. The resonant frequency and the input impedance of the antenna are altered. The bandwidth of the microstrip antenna is nearly doubled by the top loading. These changes are dependent on the displacement between the resonator and the patch. © 1994 John Wiley & Sons, Inc.
20 Jun 1994
TL;DR: In this article, a new dual-band microstrip antenna is introduced, which consists of multiple layers and is planar without any structure perpendicular to the ground plane, and the antenna is easy to fabricate.
Abstract: Microstrip antennas have many advantages over the conventional antennas except their inherent narrow bandwidth. In many applications, only distinct frequency bands may be needed instead of a continuous operating frequency range. Dual-band microstrip antennas have been suggested to cover two narrow frequency bands while retaining their advantages as microstrip antennas. A new dual-band microstrip antenna is introduced. The advantage of the proposed antenna over other available dual-band microstrip antennas is its easy fabrication. The antenna consists of multiple layers and is planar without any structure perpendicular to the ground plane. Those vertical features are difficult to fabricate and are common in other dual-band microstrip antennas. The planar structure of the multi-layer microstrip antenna is attractive from a manufacturing point of view, especially for mass production using printed-circuit technology. >
Patent•
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TL;DR: In this article, a planar antenna with an array of coaxial ring-slot radiating elements (4,5) formed through a conductive layer on a dielectric substrate is disclosed.
Abstract: A planar antenna is disclosed. The antenna (1) has an array of coaxial ring-slot radiating elements (4,5) formed through a conductive layer (3) on a dielectric substrate (2). A number of probes (14,15), coupled to the ring-slot element (4,5), excite a resonant mode on each ring-slot element (4,5). The resonant modes combine in the far field to form a directional radiation pattern. By adjustment of the relative phase difference between the excited modes, the radiation pattern can be steered in azimuth. The phase difference can be controlled by electronic phase shifting means (12,13). The radiation pattern also can be shaped in elevation by choice of the ring-slot element (4,5) geometry to support desired resonant modes.
TL;DR: In this article, the design, fabrication, testing, and analysis of a new broadband rectangular microstrip antenna element resonating at 7.200 GHz is introduced and discussed, and measured data on the performance characteristics of the new antenna element are presented and compared with the characteristics of a conventional micro strip antenna element having the same dimensions.
Abstract: The design, fabrication, testing, and analysis of a new broadband rectangular microstrip antenna element resonating at 7.200 GHz is introduced and discussed. Measured data on the performance characteristics of the new antenna element are presented and compared with the characteristics of a conventional microstrip antenna element having the same dimensions. © 1994 John Wiley & Sons, Inc.
20 Jun 1994
TL;DR: In this article, the authors applied the finite-difference time-domain (FDTD) method to the analysis of CPW-fed folded-slot antennas and compared the theoretical results and measured data.
Abstract: Folded slots are attractive for active arrays because of their broad bandwidth and simplicity. They have been used previously in a quasi-optical amplifier array. However, little is known about these antennas on thin substrates. The finite-difference time-domain (FDTD) method is applied to the analysis of CPW-fed folded-slot antennas. The paper compares the theoretical results and measured data and provides some design information for folded slots.
01 Oct 1994
TL;DR: Two new microstrip circular patches excited by a microstrip trarsmission line through an inserted coplanar section are presented and it is shown that the matching performances are improved for TM11 and TM12 modes.
Abstract: Two new microstrip circular patches excited by a microstrip trarsmission line through an inserted coplanar section are presented. The integral equation for the unknown currents on the atenna and its feeding line is solved by the method of moments in which, the triangular subdomains discretization is employed. The calculated results show that the matching performances are improved for TM11 and TM12 modes. A good agreement between our theoretical and our experimental results is obtained.
01 Apr 1994-Canadian Journal of Electrical and Computer Engineering-revue Canadienne De Genie Electrique Et Informatique
TL;DR: In this article, an analytic solution for the resonant frequency of a microstrip disk antenna with a shorting post is presented, which is then specialized to the special cases of even and odd excitations.
Abstract: This study investigates the resonant frequency of microstrip disk antennas affected by a shorting post. Initially an analytic solution for the resonant frequencies of a microstrip disk antenna with a shorting post is presented. The solution is then specialized to the special cases of even and odd excitation. These excitations further the understanding of the shorting-post size and location effects on the resonant modes. The results agree well with experimental results and indicate that the location of the shorting post may be used to control the resonant frequency and polarizations, or to cancel the unwanted modes of a microstrip disk antenna. These properties provide a means for the electronic control of microstrip disk antennas.
10 May 1994
TL;DR: The analysis of an annular ring microstrip antenna covered with lossy dielectrics is presented in this paper, where the effect of dielectric loading is not considered in the design.
Abstract: The analysis of an annular ring microstrip antenna covered with lossy dielectrics is presented in this paper It has been reported in the literature that due to dielectric loading the resonant frequency in the rectangular microstrip antenna changes The absolute value of the change increases with operating frequency, the relative permittivity and the thickness of dielectric layer This change may cause degradation in performance due to inherent narrow bandwidth of microstrip antennas if the effect of loading is not considered in the design Using variational method fractional change in the resonant frequency has been calculated for annular ring microstrip antenna and stacked annular ring microstrip antenna Experimental results are compared with numerical results and also with the rectangular microstrip antenna Eventually results are simulated on computer >
01 Oct 1994
TL;DR: In this article, an investigation of the antenna-tissue interaction using the finite-difference time-domain (FDTD) electromagnetic simulation approach is presented, coupled with detailed models of the human head and hand to provide input impedance, radiation pattern, gain, and specific absorption rate (SAR) data for different antenna configurations.
Abstract: In the design of antennas for use with hand-held transceiver devices, the electromagnetic interaction between the antenna and the nearby biological tissue is a key factor which must be considered before a design is finalized. This paper presents an investigation of this antenna-tissue interaction using the finite-difference time-domain (FDTD) electromagnetic simulation approach. Accurate models of antennas on a handset are coupled with detailed models of the human head and hand to provide input impedance, radiation pattern, gain, and specific absorption rate (SAR) data for different antenna configurations. Antenna structures such as the monopole, side-mounted planar inverted F antenna (PIFA), and back-mounted PIFA are selected as representative examples of external and internal type radiators. Experimental results are provided which support the theoretically obtained conclusions.
20 Jun 1994
TL;DR: In this paper, the resonance problem of a superstrate-loaded annular microstrip patch on a spherical body is studied and a moment method calculation is used to solve the complex resonant frequency.
Abstract: The resonant frequency of a microstrip patch antenna is a very important factor to be determined in microstrip antenna designs It is also known that the resonant frequency is sensitive to the superstate loading and the curvature variation of the microstrip antenna The resonance problem of superstrate-loaded conformal microstrip antennas with rectangular or circular patches have also been treated previously In the present article, the resonance problem of a superstrate-loaded annular microstrip patch on a spherical body is studied A full-wave analysis and a moment method calculation are used to solve the complex resonant frequency of the microstrip patch Typical numerical results of the resonant frequency and the quality factor at the TM/sub 12/ mode, obtained from the real and imaginary parts of complex resonant frequency, are presented and analyzed >
15 Feb 1994
TL;DR: The successful development of a circularly polarized microstrip array with 28 dBic of gain at 32 Gllz is described, which can be surface-mounted onto the microspacecraft and takes very little volume and mass of the spacecraft.
Abstract: JPL/NASA is currently developing microspacecraft systems for future deep space applications One of the frequency bands being investigated for microspacecraft is the Ka-band (32 GHz), which can be used with smaller equipment and provides a larger bandwidth This article describes the successful development of a circularly polarized microstrip array with 28 dBic of gain at 32 GHz This antenna, which is thin, flat, and small, can be surface-mounted onto the microspacecraft and, hence, takes very little volume and mass of the spacecraft The challenges in developing this antenna are minimizing the microstrip antenna's insertion loss and maintaining a reasonable frequency bandwidth
TL;DR: In this article, the resonant frequencies of an eccentric annular microstrip antenna were computed for different modes using the cavity model and the effect of the eccentricity of the antenna was investigated experimentally.
Abstract: The resonant frequencies of an eccentric annular microstrip antenna are computed for different modes using the cavity model. The effect of the eccentricity on the resonant frequencies is investigated. The computed resonant frequencies are verified experimentally. The measured resonant frequencies are considered to be located at the minimum locations of the return loss. The magnetic field distribution is also computed and plotted for some patches. © 1994 John Wiley & Sons, Inc.
01 Oct 1994
TL;DR: In this article, the substrate thickness of a coaxially fed microstrip antenna is increased to ensure a broad band matching, and a new working domain, monitored by an empiric law, is defined ensuring a broad-band matching.
Abstract: Increasing the substrate thickness of a coaxially fed microstrip antenna reinforces interactions between modes, and provides the antenna with specific characteristics. Then a new working domain, monitored by an empiric law, is defined ensuring a broad band matching. Such an antenna shows the same radiation pattern as one running on its fundamental mode.