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A novel scheme is presented to control the frequency response on an open-ended waveguide antenna. A groove is loaded in the waveguide that is used to independently control the frequency response of the antenna without affecting the radiation pattern, and a transition is used to provide additional control. A dual-wideband antenna is taken as an example to verify the effectiveness of the scheme. To demonstrate the idea, an antenna element and its $2\times2$ array were designed, fabricated, and measured. Reasonable agreement between the measured and simulated results has been observed. The measured 10 dB impedance bandwidths of the lower and upper bands of the proposed element are achieved to be more than 22.2% and 14.2%, respectively, fully covering the 26/28 GHz band (24.25–29.5 GHz) and 39 GHz (37–40 GHz) band. [ABSTRACT FROM AUTHOR]

This article presents a novel miniaturized almost all-angle-insensitive strong coupled frequency-selective surface (SC-FSS) with all-polarization-insensitive multiband by introducing the different interlayer coupling patches. Two templates of a single passband and a dual passband with unit cell less than $0.03\lambda $ are adopted to bring in two stopbands on both ends of each passband. Furthermore, the corresponding equivalent circuit models are developed to explain the physical mechanism and formulate relevant design equations. Finally, a prototype of the proposed dual-passband structure is fabricated and measured to verify the results of full-wave simulation and theoretical analysis. The experiment results show that there are a lower passband working at 2 GHz and a higher passband at 5.8 GHz with a lower stopband at 4 GHz and a higher at 7.5 GHz at the ends of above passbands, respectively, which exhibits the stable performance against the variation of the incident angles (from 0° to 86°) for both TE and TM polarizations. The measurement results demonstrate that the proposed multiband SC-FSS is a good candidate for designing a high-performance antenna radome for solving electromagnetic interference (EMI) problems. [ABSTRACT FROM AUTHOR]

Radio reception relies on antennas for the collection of electromagnetic fields carrying information, and receiver elements for demodulation and retrieval of the transmitted information. Here, we demonstrate an atom-based receiver for AM and FM microwave communication with a 3 dB bandwidth in the baseband of ~100 kHz that provides optical circuit-free field pickup, multiband carrier capability, and inherently high field sensitivity. The atom-based receiver exploits field-sensitive cesium Rydberg vapors in a centimeter-sized glass cell, and electromagnetically induced transparency, a quantum-optical effect, as a readout of baseband signals modulated onto carriers with frequencies ranging over four octaves, from C-band to Q-band. Receiver bandwidth, dynamic range and sideband suppression are characterized, and acquisition of audio waveforms of human vocals demonstrated. The atomic receiver is a valuable receiver technology because it does not require antenna structures and is resilient against electromagnetic interference, while affording multiband operation in a single compact receiving element. [ABSTRACT FROM AUTHOR]

In this article, a class of mode composite transmission line called mode composite sandwich slot line (MCSSL) is proposed, studied, and demonstrated. The MCSSL is composed of two substrate integrated waveguides (SIWs) and a sandwiched quasi-slot line. Structural parts of the two SIWs inherently serve as the two conductors of the quasi-slot line. The SIW supports the TE10 fundamental mode propagation, whereas the quasi-TEM mode is supported by the quasi-slot line. Two types of transition structures are proposed in this article, which enable an easier integration of the studied MCSSL with other transmission lines. An MCSSL-based antenna is designed and fabricated to theoretically and experimentally demonstrate its advantages and feasibility. It has been shown that the MCSSL features the physical and electrical characteristics of a joint structure (or structure sharing) in connection with a mode composite with planar structures, and it can find applications in broadband and multiband circuits and antenna developments. [ABSTRACT FROM AUTHOR]

A differentially fed hybrid dipole, slot, and patch antenna with unidirectional radiation patterns is designed in this article. The antenna consists of a metal strip, a patch loaded with a slot, and a simple wideband 180° out-of-phase power splitter (OPS). The OPS can generate two signals with the same amplitude but accurate phase difference of 180° to achieve one-port differential feeding. The hybrid modes of different types of antennas, i.e., dipole, patch, and slot, are excited to obtain five bands. Additionally, the TM01, TM21, and TM03 modes of the patch antenna are excited. By loading the slot and the metal strip, the radiation pattern of TM21 mode is converted from conical to broadside, and the ground walls further concentrate the radiation pattern. The ground walls also enhance the antenna gain, with the increments of 1 dB at 3.5 GHz, 3.4 dB at 4.65 GHz, 4.1 dB at 5.5 GHz, and 1.4 dB at 6.3 GHz. Finally, the antenna is fabricated and measured. The measured results show that the antenna covers five impedance bandwidths (IMBWs) of 1.85–1.91 GHz (3.2%), 3.13–3.66 GHz (15.6%), 4.62–4.98 GHz (7.5%), 5.10–5.82 GHz (13.2%), and 6.10–6.57 GHz (7.4%) for $\vert \,\,{S} _{11}\vert < - 10$ dB. The radiation patterns at each band are toward the broadside, with peak gains of 5.1 dBi at 1.85 GHz, 8.8 dBi at 3.45 GHz, 8.8 dBi at 4.7 GHz, 12.2 dBi at 5.5 GHz, and 9.7 dBi at 6.3 GHz. [ABSTRACT FROM AUTHOR]

The theory of inner resonant modes (IRMs) is very useful for the analysis and design of dielectric resonator antennas (DRAs), but it suffers from several limitations including canonical DRA shapes, high permittivity substrate, and large errors. Characteristic modes (CMs) contain similar physical insights but without the limitations owing to its full-wave nature. In this paper, a new approach is proposed for the codesign of DRAs and feeding structures using CMs. The volume-surface formulation combining substructure treatment is adopted to calculate CMs of DRAs. To detailedly demonstrate the proposed method, electric and magnetic feeding structures are utilized to excite a cubic DRA as examples. Compared with the results obtained by an isolated design of DRAs and feeding structures, characteristic mode analysis (CMA) of the whole structure reveals several new modes, in which the lower order modes correspond to much lower resonant frequencies. Proper modifications of the feeding structures can effectively excite these modes and result in dual- and triple-band operation. Several prototypes were fabricated and measured for verification. For a cubic DRA with a side length of 25.4 mm, it achieves a triple-band operation at 1.6, 3.1, and 4.6 GHz. Therefore, this method is ideal for the codesign of arbitrary DRAs with feeding structures. [ABSTRACT FROM AUTHOR]

A novel coaperture antenna based on the concept of mode composite transmission line and named mode composite antenna (MCA) is proposed in this communication. The MCA combines the structure of a monopole antenna and a substrate integrated waveguide (SIW) slot antenna to form a new coaperture antenna. Because of the structure sharing characteristic in MCA, it can reduce the size of the antenna. The MCA serves as the monopole antenna supporting the surface current on the antenna patch in its low-band operation. In its high-band operation, the SIW will support TE10 to excite the slot array. The two-mode operation has high isolation which makes the MCA a promising candidate for multiband application. The measured and simulated results agreed well and validated the feasibility of the MCA. [ABSTRACT FROM AUTHOR]

A systematic design method for high-order dual-band bandpass frequency selective surfaces (FSSs) with a low profile is derived from classical filter theory and presented here. To complement the design procedure, a multilayer double-slot resonator unit cell topology is proposed for realizing dual-band operations. For simplicity, the resonators are made to work for only a single polarization. To design the FSS, first, a classical dual-band bandpass filter circuit is designed by performing successive frequency transformations on a lowpass prototype. The filter is then transformed into a form resembling the equivalent circuit of the proposed multilayer FSS structure. Finally, the transformed filter is mapped to a set of FSS geometrical parameters. The method presents very few inherent limitations to realizing a diverse range of filter responses. The resulting designs lend themselves to fabrication since very few layers of metallization are required. Two FSSs with third-order passbands at 4 and 7 GHz but different passband characteristics are designed and verified numerically. One of the designs is fabricated and experimentally verified. The overall thickness of the designs is $0.08\lambda _{l}$ where $\lambda _{l}$ is the free-space wavelength at 4 GHz. The unit cell size is approximately $\lambda _{l}/8$. [ABSTRACT FROM AUTHOR]

A systematic technique for designing and optimizing multilayer frequency selective surfaces (FSSs) with low overall profile is presented. Periodic scatterers in the shape of loaded dipoles (dogbones) are used on each layer to create a single-stopband response. Multiple such layers are cascaded together to create the desired multistopband response. An equivalent circuit model for a multilayer FSS that explicitly and intuitively accounts for electromagnetic coupling interactions between the layers is proposed and investigated. This model is used in a novel design method, which precompensates for the effect of coupling during circuit-based design stage rather than postcompensating through iterative full-wave (FW) optimization after the design stage, as in most traditional approaches. As a consequence, this approach has the potential to greatly speed up the design process by enabling considerable simplifications during FW simulations. The proposed method is used to design several ultralow-profile triple-layer, triple-stopband surfaces intended for Wi-Fi applications. The interlayer spacing is as low as $\lambda /75$ at the highest operating band (5.2 GHz), making the overall thickness extremely small. The unit cell size for the designs is about $\lambda /5$ at 5.2 GHz. The designs are fabricated and tested to validate the proposed methodology. [ABSTRACT FROM PUBLISHER]

Additional resonances are often introduced in an inverted-F antenna (IFA) by modifying the “F” structure, which typically makes the antenna both complex and bulky. To mitigate this problem, novel dual-/tri-band conformal capsule antennas with simple configuration are proposed in this paper by modifying the ground of the IFA and shifting the feed point. With these modifications, the IFA is miniaturized, and yet it is able to simultaneously cover the MedRadio band (401-406 MHz) and ISM bands (902-928 MHz and/or 2.4-2.5 GHz). The resulting configurations remain simple and compact despite the modifications, which is very desirable for conformal capsule type of applications. Furthermore, the impedance matching characteristics of the proposed IFAs remain stable even when a battery is added inside the capsule and the size or the position of the battery is modified. Moreover, the impedance matching of the antenna continues to remain stable even as its surrounding environment is changed. The operating principle of the proposed dual-/tri-band IFAs is discussed in detail and parametric study is carried out to investigate the characteristics of the proposed antennas. The results of this paper are expected to be helpful for designing multiband antennas in the future. [ABSTRACT FROM PUBLISHER]

An frequency selective surface (FSS) structure based on parallel LC resonators is proposed to achieve multiband bandpass filtering responses. The parallel LC resonator, implemented by a via-connected metallic line and a parallel-plate capacitor (PPC), serves as the basic element for intentionally constructing FSS unit cell, which exhibits a single-band bandpass filtering response. As a result, the proposed FSS structure can provide a multiband performance by introducing multiple VCMLs and PPCs with different resonance frequencies. Because of the compact resonator resulting from a PPC, the proposed FSSs feature miniaturized unit cell size inherently, for example, the single-band FSS element is as compact as 4.8% of the operating wavelength. Moreover, this kind of FSS structure is also beneficial for independent control of the frequency performance under different polarizations, efficient optimal design of desired resonance frequencies, and easy realization of multiband response with wideband ratio range (e.g., 1.13 to 3.32 for the dual-band FSS). Equivalent circuits of these FSSs are established for explaining the resonating mechanisms and precisely modeling the frequency performances. Finally, prototypes of the dual- and tri-band FSSs are fabricated and measured. The measured results exhibit stable filtering performance under different polarizations and incidence angles (up to 60°). [ABSTRACT FROM PUBLISHER]

The design of a quad-band (18, 28, 38, and 48 GHz) feed horn is presented. Corrugations are used for a good polarization purity at the higher frequencies. At the lower frequency, they act as a smooth wall and the horn profile is tuned to achieve a high aperture efficiency. [ABSTRACT FROM AUTHOR]

A low-profile tri-band inverted-F antenna (TIFA) is proposed for narrowband vehicle-based applications in upper HF and lower VHF ranges. A driven element, engineered as an inverted-F antenna, operates at the lowest frequency of 27 MHz, while two parasitic elements, built as inverted-L monopoles, enable resonances at 49 and 53 MHz. The standalone antenna height over a ground plane is \lambda /25 at the lowest band. When mounted on a vehicle and bent to follow its profile, TIFA maintains similar performance with only \lambda /44 height above the vehicle’s roof. To eliminate the need for external matching network, the driven element is offset fed. The \bf VSWR \leq 2:1 bandwidth of the first band is greater than 1%, whereas the bandwidths of the two VHF bands are narrower and do not exceed 0.4%. To mitigate possible detuning and enable full utilization of the FCC approved bandwidths, a simple approach for tuning the resonance is outlined. Scaled models of TIFA and vehicle are built and impedance and pattern measurements are conducted. Obtained results confirm the proposed antenna is a viable candidate for (among other applications) communication with remotely controlled ground and flying vehicles/toys. [ABSTRACT FROM PUBLISHER]

A negative-refractive-index transmission-line (NRI-TL) metamaterial-loaded dipole antenna is proposed, which has a fully printed configuration and exhibits multiband performance. The antenna consists of a conventional dipole antenna loaded with two unequal parallel NRI-TL metamaterial unit cells which have the same electrical length, but each is loaded with a thin inductive strip that has a different length and therefore a different effective shunt inductance. An equivalent circuit is extracted to investigate the performance of the proposed metamaterial-loaded dipole antenna by modeling each of the dipole arms as a transmission line. This circuit is then used to verify that the resonant behavior of the proposed antenna can be altered by simply adjusting the lengths of the thin inductive strips. A fabricated prototype has compact dimensions of 40 \mathrmmm \times 10 \mathrmmm\times 1.6 \mathrmmm, and exhibits good agreement between the measured and simulated results. [ABSTRACT FROM PUBLISHER]

A novel design strategy for multi-standard mobile handset antennas is presented and verified with experimental results. The results show that the presented antenna operates with better than -3 dB (50%) efficiency across the frequencies of 698–2900 MHz and 3250–3600 MHz, thus having state-of-the-art performance. The antenna is shown to have a robust performance with a user, and it can fulfill the specific absortion rate (SAR) and hearing aid compatibility (HAC) requirements. In addition, it is demonstrated how the multi-antenna functionality can be included within the antenna structure, simultaneously achieving a small antenna volume of 750 mm^3. The diversity gain and isolation are better than 10 dB at the frequency band 2110–3600 MHz. Hence, the proposed antenna is well suited for future LTE-A mobile handsets. [ABSTRACT FROM PUBLISHER]

A compact multiresonator-loaded planar antenna for multiband operation is presented. Multiresonator-loaded structures including a pair of symmetrical edge resonators and a T-shaped stub resonator are employed. By loading these resonators, a U-shaped monopole antenna can yield three independent resonances while achieving a compact size of 18\times 19\ mm^2. The experimental results demonstrate that the proposed antenna is capable of operating over the 2.40–2.51 GHz, 3.35–3.94 GHz and 5.02–6.63 GHz frequency ranges, which is suitable for WLAN 2.4/5.2/5.8 GHz and WiMAX 3.5 GHz applications. [ABSTRACT FROM PUBLISHER]

A novel multi-band design of planar slot antenna with compact operation for IEEE 802.16m WiMAX system is proposed. With the use of C- and inverted L-shaped slots, multi resonant modes close to 2.6/3.5/5.5 GHz bands can be excited to meet the specifications of WiMAX system (IEEE 802.16m). The obtained impedance bandwidth across these operating bands can reach about 525/743/813 MHz for the 2.6/3.5/5.5 GHz bands, respectively. We derive more than 10% reduction in antenna size and gain compact operation only from 32\,\times\,14\,\times\,0.8 mm^3 antenna dimension. The measured peak gains and total radiation efficiencies are about 3.0/4.3/5.2 dBi and 88/95/97% for the 2.6/3.5/5.5 GHz bands, respectively, with nearly omni-directional pattern in the XY-plane. [ABSTRACT FROM PUBLISHER]

A compact, fully-printed negative-refractive-index transmission-line (NRI-TL) metamaterial-loaded dipole antenna is proposed, which exhibits multiband resonant characteristics that are not harmonically related. The multiband behavior is achieved by loading a host dipole antenna with series capacitive gaps and shunt inductive strips, to form a two unit-cell NRI-TL loaded antenna. By modeling the right-handed dipole sections as biconical transmission lines, the rich dispersion properties of the NRI-TL structure can be exploited, while still creating an effective radiator. An equivalent circuit model of the NRI-TL antenna is developed, and it is shown that its performance agrees well with the results obtained using full-wave simulations. It is also shown that the resonant behavior of the antenna can be adjusted by changing its geometrical parameters, which in turn tune the loading parameters of each NRI-TL unit cell. As such, both dual-band and triband versions of the antenna are designed and fabricated. The dual-band version exhibits three distinct resonances at 1.15, 2.88, and 3.72 GHz, with measured -10 dB bandwidths of 37 and 1150 MHz. The lowest resonance at 1.15 GHz corresponds to a 47% reduction in the resonant frequency compared to that of a reference unloaded dipole antenna, which translates into a size miniaturization factor of approximately two. The antenna exhibits stable dipolar radiation patterns with a linear electric field polarization, and has a total size of 50\times 10\times 0.79\ mm^3 or 0.19\lambda0\times 0.04\lambda0\times 0.003\lambda0 at 1.15 GHz. Throughout the operating bands the measured gain and radiation efficiency vary from 0.11 to 3.26 dBi and 49.5% to 95.6%, respectively. [ABSTRACT FROM PUBLISHER]

A novel Koch-like fractal curve is proposed to transform ultra-wideband (UWB) bow-tie into so called Koch-like sided fractal bow-tie dipole. A small isosceles triangle is cut off from center of each side of the initial isosceles triangle, then the procedure iterates along the sides like Koch curve does, forming the Koch-like fractal bow-tie geometry. The fractal bow-tie of each iterative is investigated without feedline in free space for fractal trait unveiling first, followed by detailed expansion upon the four-iterated pragmatic fractal bow-tie dipole fed by 50-\Omega coaxial SMA connector through coplanar stripline (CPS) and comparison with Sierpinski gasket. The fractal bow-tie dipole can operate in multiband with moderate gain (3.5–7 dBi) and high efficiency (60%-80%), which is corresponding to certain shape parameters, such as notch ratio \alpha, notch angle \varphi, and base angles \theta of the isosceles triangle. Compared with conventional bow-tie dipole and Sierpinski gasket with the same size, this fractal-like antenna has almost the same operating properties in low frequency and better radiation pattern in high frequency in multi-band operation, which makes it a better candidate for applications of PCS, WLAN, WiFi, WiMAX, and other communication systems. [ABSTRACT FROM PUBLISHER]

A handset antenna technique combining a parallel excitation of a PIFA and a slot is presented. The number of frequency bands is given by the sum of bands given per each radiator which can be controlled independently. Component interaction (battery, display, and speaker) is analyzed to determine the best place to mitigate performance degradation. Finally, a concept featuring a small footprint (39 × 11 mm²) and low profile (2 mm) is proposed for multiband operation. [ABSTRACT FROM AUTHOR]

An inverted-FL antenna is proposal with a self-complementary structure. This unique design is realized by integrating an inverted-F antenna with a self-complementary structure and an inverted-L element. The proposed antenna with a volume of 10 x 10 x 45mm3 achieves a constant impedance of 188 Ω without attaching a matching load required since a self-complementary antenna of an axially symmetric type has constant impedance. This antenna acquired broadband and multiband characteristics covering the GSM850/GSM900/DCS/ PCS/UMTS2100/UMTS2600 bands and the 2.5G/3.5G bands for Mobile-WiMAX by simulation and measurement. [ABSTRACT FROM AUTHOR]

It is well known that a multiband frequency selective surface (FSS) can be obtained by arranging multiple simple apertures in a periodic array. However, this simple combination can not achieve a perfect resonance response in a wide band due to the restriction of the grating lobe frequency determined by the array. A new type of element, the multiperiodicity combined element (MPCE), is presented to solve this problem. Its feasibility on restraining the grating lobes is proven by numerical experiments and theoretical analysis. The electromagnetic performance of the MPCEs was studied. The results show that the MPCE FSSs have much weaker grating lobes than the traditional FSSs and their frequency performance can be well predicted through the properties of the member element FSSs. An approximate formula for predicting the transmission coefficients of the grating lobes is provided. [ABSTRACT FROM AUTHOR]

Two-arm sinuous antennas are introduced in this paper. The proposed configurations and realized phase progressions result in a unique multiband behavior with alternating polarization handedness between adjacent bands. Two sinuous embodiments are presented: a planar, cavity backed, flush mountable design and a unidirectional, conically projected structure. Both designs exhibit multiband and multipolarized performance with low axial ratio and good pattern symmetry. Conical sinuous has superior impedance matching, wider bandwidth for all circularly polarized bands and does not require absorber backing for unidirectional radiation. A computer aided analysis is performed using method of moments and finite element codes and results are favorably compared with measurements. [ABSTRACT FROM AUTHOR]

Modern personal communication handsets are shrinking in size and are required to operate at multiple frequency bands for enhanced functionality and performance. This poses an important challenge for antenna designers to build multiband antennas within the limited allowable space. In this paper, an internal antenna covering seven frequency bands is presented for personal communication handsets. The proposed antenna operates at GSM (880-960 MHz), DCS (1710-1880 MHz), PCS (1880-1990 MHz), UMTS (1900-2170 MHz), WiBro (2300-2390 MHz), Bluetooth (2.4-2.48 GHz), and WLAN (5.0-5.5 GHz) frequency bands. Measured input return loss of the antenna is better than -10 dB at all the frequency bands with reasonable radiation performance. Antenna volume is 30 mm x 15 mm x 4.0 mm (1.8 cm3) that makes it attractive for modern multiband and multifunctional slim handsets. [ABSTRACT FROM AUTHOR]

A novel internal, quad-band antenna placed inside a "foldable" type of mobile phone is presented. Its structure consists of a helical and a monopole element exciting two broad frequency bands. Using a simple matching circuit the proposed antenna covers several frequency bands including the global system for mobile communication (890-960 MHz), digital communication system (1710-1880 MHz), personal communication system (1850-1990 MHz), and universal mobile telecommunication system (1920-2170 MHz). It achieves a voltage standing wave ratio (VSWR) of less than three across all frequency bands with total radiation efficiency of more than 50%. Its novel design and structure occupies only 1.8 cm³ of volume making this antenna very small and very suitable for internal use inside mobile terminals. [ABSTRACT FROM AUTHOR]

The benefits resulting from the inclusion of ferrite in material loaded antennas are investigated, initially through the use of a spherical analytic model and then through a transmission line matrix simulation tool applied to a rectangular slab geometry. It is observed that a material with equality of relative permittivity and permeability in combination with specific positioning of the antenna in relation to the head, can result in the definitive small- size, high efficiency and bandwidth, low specific absorption rate (SAR) antenna. The accuracy of the simulations is validated both through efficiency and SAR measurements of three material coated monopole samples. Further research into optimizing the above attributes and translating them into a handset antenna leads to a multiband antenna design covering the GSM 1800, 1900, UMTS and Bluetooth bands, with a SAR value reduced by 88% compared to conventional phones and an efficiency of 38% at 1.8 GHz. A tri-band antenna design is also presented, utilizing currently available lossy ferrite material and it is considered as the first step towards the feasibility of the ultimate low SAR multiband ferrite handset antenna, until further material development specifically for antenna applications takes place. [ABSTRACT FROM AUTHOR]

Combining the concepts of pulse fidelity, time-domain correlation patterns, and frequency-domain pattern stability, we propose the concept of frequency-domain correlation patterns and a figure of merit, called pattern stability factor (PSF), to characterize pattern stability of wideband antennas. The frequency-domain correlation pattern represents the relationship between radiation in a reference direction to radiation in all other directions of interest, over a specified bandwidth. With practical examples, we demonstrate that this tool is very useful when selecting a single transfer function (and a reference direction) for the antenna when designing or optimizing an ultrawideband (UWB) system. Careful selection of the reference direction is crucial for antennas with relatively less stable patterns, but even antennas with relatively stable patterns can perform poorly overall if an inappropriate reference direction is chosen. The PSF represents the overall pattern stability of an antenna for a specific bandwidth and a range of directions. It is useful as a quantitative measure: a) to compare the suitability of different antennas for a given wideband or multiband application; b) to assess pattern stability improvement methods; and c) to quantify the effect of packaging, etc., on stability. We also propose the concept of PSF bandwidth and show how it can be used to identify stable frequency bands of a given antenna within its impedance bandwidth, and how it compares with the impedance bandwidth of some UWB antennas [ABSTRACT FROM PUBLISHER]

This paper presents a compact phased-array antenna transceiver system that can operate over a wide bandwidth from 10 to 35 GHz with the abilities of beam scanning and full-duplex communication. The system consists of ultrawide-band Vivaldi antennas, a multiline PET-based phase shifter, a six-channel microstrip multiplexer, and monolithic microwave integrated circuit (MMIC) amplifiers. The multiplexer routes 10, 19, and 32 GHz signals to the transmit path and 12, 21, and 35 GHz signals to the receive path. The multiplexer shows insertion loss between 2.2 and 3.4 dB for all six channels and together with wide-band MMIC amplifiers plays an important role to build a compact, multifrequency, and full-duplex transceiver system. The system should have many applications in multiband satellite communication systems and radar systems. [ABSTRACT FROM PUBLISHER]